path: root/static/freebsd/man9/sysctl.9 3.html

<table class="head">
  <tr>
    <td class="head-ltitle">SYSCTL(9)</td>
    <td class="head-vol">Kernel Developer's Manual</td>
    <td class="head-rtitle">SYSCTL(9)</td>
  </tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">SYSCTL_DECL</code>,
    <code class="Nm">SYSCTL_ADD_BOOL</code>,
    <code class="Nm">SYSCTL_ADD_COUNTER_U64</code>,
    <code class="Nm">SYSCTL_ADD_COUNTER_U64_ARRAY</code>,
    <code class="Nm">SYSCTL_ADD_INT</code>,
    <code class="Nm">SYSCTL_ADD_LONG</code>,
    <code class="Nm">SYSCTL_ADD_NODE</code>,
    <code class="Nm">SYSCTL_ADD_NODE_WITH_LABEL</code>,
    <code class="Nm">SYSCTL_ADD_OPAQUE</code>,
    <code class="Nm">SYSCTL_ADD_PROC</code>,
    <code class="Nm">SYSCTL_ADD_QUAD</code>,
    <code class="Nm">SYSCTL_ADD_ROOT_NODE</code>,
    <code class="Nm">SYSCTL_ADD_S8</code>,
    <code class="Nm">SYSCTL_ADD_S16</code>,
    <code class="Nm">SYSCTL_ADD_S32</code>,
    <code class="Nm">SYSCTL_ADD_S64</code>,
    <code class="Nm">SYSCTL_ADD_SBINTIME_MSEC</code>,
    <code class="Nm">SYSCTL_ADD_SBINTIME_USEC</code>,
    <code class="Nm">SYSCTL_ADD_STRING</code>,
    <code class="Nm">SYSCTL_ADD_CONST_STRING</code>,
    <code class="Nm">SYSCTL_ADD_STRUCT</code>,
    <code class="Nm">SYSCTL_ADD_TIMEVAL_SEC</code>,
    <code class="Nm">SYSCTL_ADD_U8</code>,
    <code class="Nm">SYSCTL_ADD_U16</code>,
    <code class="Nm">SYSCTL_ADD_U32</code>,
    <code class="Nm">SYSCTL_ADD_U64</code>,
    <code class="Nm">SYSCTL_ADD_UAUTO</code>,
    <code class="Nm">SYSCTL_ADD_UINT</code>,
    <code class="Nm">SYSCTL_ADD_ULONG</code>,
    <code class="Nm">SYSCTL_ADD_UMA_CUR</code>,
    <code class="Nm">SYSCTL_ADD_UMA_MAX</code>,
    <code class="Nm">SYSCTL_ADD_UQUAD</code>,
    <code class="Nm">SYSCTL_CHILDREN</code>,
    <code class="Nm">SYSCTL_STATIC_CHILDREN</code>,
    <code class="Nm">SYSCTL_NODE_CHILDREN</code>,
    <code class="Nm">SYSCTL_PARENT</code>, <code class="Nm">SYSCTL_BOOL</code>,
    <code class="Nm">SYSCTL_COUNTER_U64</code>,
    <code class="Nm">SYSCTL_COUNTER_U64_ARRAY</code>,
    <code class="Nm">SYSCTL_INT</code>,
    <code class="Nm">SYSCTL_INT_WITH_LABEL</code>,
    <code class="Nm">SYSCTL_LONG</code>,
    <code class="Nm">sysctl_msec_to_ticks</code>,
    <code class="Nm">SYSCTL_NODE</code>,
    <code class="Nm">SYSCTL_NODE_WITH_LABEL</code>,
    <code class="Nm">SYSCTL_OPAQUE</code>, <code class="Nm">SYSCTL_PROC</code>,
    <code class="Nm">SYSCTL_QUAD</code>,
    <code class="Nm">SYSCTL_ROOT_NODE</code>, <code class="Nm">SYSCTL_S8</code>,
    <code class="Nm">SYSCTL_S16</code>, <code class="Nm">SYSCTL_S32</code>,
    <code class="Nm">SYSCTL_S64</code>,
    <code class="Nm">SYSCTL_SBINTIME_MSEC</code>,
    <code class="Nm">SYSCTL_SBINTIME_USEC</code>,
    <code class="Nm">SYSCTL_STRING</code>,
    <code class="Nm">SYSCTL_CONST_STRING</code>,
    <code class="Nm">SYSCTL_STRUCT</code>,
    <code class="Nm">SYSCTL_TIMEVAL_SEC</code>,
    <code class="Nm">SYSCTL_U8</code>, <code class="Nm">SYSCTL_U16</code>,
    <code class="Nm">SYSCTL_U32</code>, <code class="Nm">SYSCTL_U64</code>,
    <code class="Nm">SYSCTL_UINT</code>, <code class="Nm">SYSCTL_ULONG</code>,
    <code class="Nm">SYSCTL_UMA_CUR</code>,
    <code class="Nm">SYSCTL_UMA_MAX</code>, <code class="Nm">SYSCTL_UQUAD</code>
    &#x2014; <span class="Nd">Dynamic and static sysctl MIB creation
    functions</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="In">#include
    &lt;<a class="In">sys/param.h</a>&gt;</code>
  <br/>
  <code class="In">#include &lt;<a class="In">sys/sysctl.h</a>&gt;</code></p>
<p class="Pp"><code class="Fn">SYSCTL_DECL</code>(<var class="Fa" style="white-space: nowrap;">name</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_BOOL</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">bool *ptr</var>,
    <var class="Fa">uint8_t val</var>, <var class="Fa">const char
  *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_COUNTER_U64</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>,
    <var class="Fa">counter_u64_t *ptr</var>, <var class="Fa">const char
    *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_COUNTER_U64_ARRAY</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>,
    <var class="Fa">counter_u64_t *ptr</var>, <var class="Fa">intmax_t
    len</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_INT</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">int *ptr</var>,
    <var class="Fa">int val</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_LONG</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">long *ptr</var>,
    <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_NODE</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">int
    (*handler)(SYSCTL_HANDLER_ARGS)</var>, <var class="Fa">const char
    *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_NODE_WITH_LABEL</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">int
    (*handler)(SYSCTL_HANDLER_ARGS)</var>, <var class="Fa">const char
    *descr</var>, <var class="Fa">const char *label</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_OPAQUE</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">void
    *ptr</var>, <var class="Fa">intptr_t len</var>, <var class="Fa">const char
    *format</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_PROC</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">void *arg1</var>,
    <var class="Fa">intptr_t arg2</var>, <var class="Fa">int (*handler)
    (SYSCTL_HANDLER_ARGS)</var>, <var class="Fa">const char *format</var>,
    <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_QUAD</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">int64_t *ptr</var>,
    <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_ROOT_NODE</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">int number</var>,
    <var class="Fa">const char *name</var>, <var class="Fa">int ctlflags</var>,
    <var class="Fa">int (*handler)(SYSCTL_HANDLER_ARGS)</var>,
    <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_S8</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">int8_t *ptr</var>,
    <var class="Fa">int8_t val</var>, <var class="Fa">const char
  *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_S16</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">int16_t *ptr</var>,
    <var class="Fa">int16_t val</var>, <var class="Fa">const char
  *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_S32</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">int32_t *ptr</var>,
    <var class="Fa">int32_t val</var>, <var class="Fa">const char
  *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_S64</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">int64_t *ptr</var>,
    <var class="Fa">int64_t val</var>, <var class="Fa">const char
  *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_SBINTIME_MSEC</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">sbintime_t
    *ptr</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_SBINTIME_USEC</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">sbintime_t
    *ptr</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_STRING</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">char
    *ptr</var>, <var class="Fa">intptr_t len</var>, <var class="Fa">const char
    *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_CONST_STRING</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">const char
    *ptr</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_STRUCT</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">void
    *ptr</var>, <var class="Fa">struct_type</var>, <var class="Fa">const char
    *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_TIMEVAL_SEC</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">struct
    timeval *ptr</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_U8</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">uint8_t *ptr</var>,
    <var class="Fa">uint8_t val</var>, <var class="Fa">const char
  *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_U16</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">uint16_t *ptr</var>,
    <var class="Fa">uint16_t val</var>, <var class="Fa">const char
    *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_U32</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">uint32_t *ptr</var>,
    <var class="Fa">uint32_t val</var>, <var class="Fa">const char
    *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_U64</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">uint64_t *ptr</var>,
    <var class="Fa">uint64_t val</var>, <var class="Fa">const char
    *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_UINT</code>(<var class="Fa">struct sysctl_ctx_list
    *ctx</var>, <var class="Fa">struct sysctl_oid_list *parent</var>,
    <var class="Fa">int number</var>, <var class="Fa">const char *name</var>,
    <var class="Fa">int ctlflags</var>, <var class="Fa">unsigned int *ptr</var>,
    <var class="Fa">unsigned int val</var>, <var class="Fa">const char
    *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_ULONG</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">unsigned
    long *ptr</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_UQUAD</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">uint64_t
    *ptr</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_UMA_CUR</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">uma_zone_t
    ptr</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_UMA_MAX</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">uma_zone_t
    ptr</var>, <var class="Fa">const char *descr</var>); <var class="Fa">const
    char *descr</var>
  <br/>
  <var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_ADD_UAUTO</code>(<var class="Fa">struct
    sysctl_ctx_list *ctx</var>, <var class="Fa">struct sysctl_oid_list
    *parent</var>, <var class="Fa">int number</var>, <var class="Fa">const char
    *name</var>, <var class="Fa">int ctlflags</var>, <var class="Fa">void
    *ptr</var>, <var class="Fa">const char *descr</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid_list *</var>
  <br/>
  <code class="Fn">SYSCTL_CHILDREN</code>(<var class="Fa">struct sysctl_oid
    *oidp</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid_list *</var>
  <br/>
  <code class="Fn">SYSCTL_STATIC_CHILDREN</code>(<var class="Fa">struct
    sysctl_oid_list OID_NAME</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid_list *</var>
  <br/>
  <code class="Fn">SYSCTL_NODE_CHILDREN</code>(<var class="Fa">parent</var>,
    <var class="Fa">name</var>);</p>
<p class="Pp"><var class="Ft">struct sysctl_oid *</var>
  <br/>
  <code class="Fn">SYSCTL_PARENT</code>(<var class="Fa">struct sysctl_oid
    *oid</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_BOOL</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_COUNTER_U64</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_COUNTER_U64_ARRAY</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">len</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_INT</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_INT_WITH_LABEL</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>,
    <var class="Fa" style="white-space: nowrap;">label</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_LONG</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><var class="Ft">int</var>
  <br/>
  <code class="Fn">sysctl_msec_to_ticks</code>(<var class="Fa" style="white-space: nowrap;">SYSCTL_HANDLER_ARGS</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_NODE</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">handler</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_NODE_WITH_LABEL</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">handler</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>,
    <var class="Fa" style="white-space: nowrap;">label</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_OPAQUE</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">len</var>,
    <var class="Fa" style="white-space: nowrap;">format</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_PROC</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">arg1</var>,
    <var class="Fa" style="white-space: nowrap;">arg2</var>,
    <var class="Fa" style="white-space: nowrap;">handler</var>,
    <var class="Fa" style="white-space: nowrap;">format</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_QUAD</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_ROOT_NODE</code>(<var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">handler</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_S8</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_S16</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_S32</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_S64</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_SBINTIME_MSEC</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_SBINTIME_USEC</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_STRING</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">arg</var>,
    <var class="Fa" style="white-space: nowrap;">len</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_CONST_STRING</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">arg</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_STRUCT</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">struct_type</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_TIMEVAL_SEC</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_U8</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_U16</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_U32</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_U64</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_UINT</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_ULONG</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_UQUAD</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">val</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_UMA_MAX</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
<p class="Pp"><code class="Fn">SYSCTL_UMA_CUR</code>(<var class="Fa" style="white-space: nowrap;">parent</var>,
    <var class="Fa" style="white-space: nowrap;">number</var>,
    <var class="Fa" style="white-space: nowrap;">name</var>,
    <var class="Fa" style="white-space: nowrap;">ctlflags</var>,
    <var class="Fa" style="white-space: nowrap;">ptr</var>,
    <var class="Fa" style="white-space: nowrap;">descr</var>);</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The <code class="Nm">SYSCTL</code> kernel interface allows dynamic
    or static creation of <a class="Xr">sysctl(8)</a> MIB entries. All static
    sysctls are automatically destroyed when the module which they are part of
    is unloaded. Most top level categories are created statically and are
    available to all kernel code and its modules.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION_OF_ARGUMENTS"><a class="permalink" href="#DESCRIPTION_OF_ARGUMENTS">DESCRIPTION
  OF ARGUMENTS</a></h1>
<dl class="Bl-tag">
  <dt><var class="Fa">ctx</var></dt>
  <dd>Pointer to sysctl context or NULL, if no context. See
      <a class="Xr">sysctl_ctx_init(9)</a> for how to create a new sysctl
      context. Programmers are strongly advised to use contexts to organize the
      dynamic OIDs which they create because when a context is destroyed all
      belonging sysctls are destroyed as well. This makes the sysctl cleanup
      code much simpler. Else deletion of all created OIDs is required at module
      unload.</dd>
  <dt id="SYSCTL_STATIC_CHILDREN"><var class="Fa">parent</var></dt>
  <dd>A pointer to a <code class="Li">struct sysctl_oid_list</code>, which is
      the head of the parent's list of children. This pointer is retrieved using
      the
      <a class="permalink" href="#SYSCTL_STATIC_CHILDREN"><code class="Fn">SYSCTL_STATIC_CHILDREN</code></a>()
      macro for static sysctls and the
      <a class="permalink" href="#SYSCTL_CHILDREN"><code class="Fn" id="SYSCTL_CHILDREN">SYSCTL_CHILDREN</code></a>()
      macro for dynamic sysctls. The
      <a class="permalink" href="#SYSCTL_PARENT"><code class="Fn" id="SYSCTL_PARENT">SYSCTL_PARENT</code></a>()
      macro can be used to get the parent of an OID. The macro returns NULL if
      there is no parent.</dd>
  <dt><var class="Fa">number</var></dt>
  <dd>The OID number that will be assigned to this OID. In almost all cases this
      should be set to <code class="Dv">OID_AUTO</code>, which will result in
      the assignment of the next available OID number.</dd>
  <dt><var class="Fa">name</var></dt>
  <dd>The name of the OID. The newly created OID will contain a copy of the
      name.</dd>
  <dt><var class="Fa">ctlflags</var></dt>
  <dd>A bit mask of sysctl control flags. See the section below describing all
      the control flags.</dd>
  <dt><var class="Fa">arg1</var></dt>
  <dd>First callback argument for procedure sysctls.</dd>
  <dt><var class="Fa">arg2</var></dt>
  <dd>Second callback argument for procedure sysctls.</dd>
  <dt><var class="Fa">len</var></dt>
  <dd>The length of the data pointed to by the <var class="Fa">ptr</var>
      argument. For string type OIDs a length of zero means that
      <a class="Xr">strlen(3)</a> will be used to get the length of the string
      at each access to the OID. For array type OIDs the length must be greater
      than zero.</dd>
  <dt><var class="Fa">ptr</var></dt>
  <dd>Pointer to sysctl variable or string data. For sysctl values the pointer
      can be SYSCTL_NULL_XXX_PTR which means the OID is read-only and the
      returned value should be taken from the <var class="Fa">val</var>
      argument.</dd>
  <dt><var class="Fa">val</var></dt>
  <dd>If the <var class="Fa">ptr</var> argument is SYSCTL_NULL_XXX_PTR, gives
      the constant value returned by this OID. Else this argument is not
    used.</dd>
  <dt><var class="Fa">struct_type</var></dt>
  <dd>Name of structure type.</dd>
  <dt><var class="Fa">handler</var></dt>
  <dd>A pointer to the function that is responsible for handling read and write
      requests to this OID. There are several standard handlers that support
      operations on nodes, integers, strings and opaque objects. It is possible
      to define custom handlers using the <code class="Fn">SYSCTL_PROC</code>()
      macro or the <code class="Fn">SYSCTL_ADD_PROC</code>() function.</dd>
  <dt><var class="Fa">format</var></dt>
  <dd>A pointer to a string which specifies the format of the OID in a symbolic
      way. This format is used as a hint by <a class="Xr">sysctl(8)</a> to apply
      proper data formatting for display purposes.
    <p class="Pp">Current formats:</p>
    <div class="Bd-indent">
    <dl class="Bl-tag Bl-compact">
      <dt id="N"><a class="permalink" href="#N"><code class="Cm">N</code></a></dt>
      <dd>node</dd>
      <dt id="A"><a class="permalink" href="#A"><code class="Cm">A</code></a></dt>
      <dd><a class="permalink" href="#char"><code class="Li" id="char">char
          *</code></a></dd>
      <dt id="C"><a class="permalink" href="#C"><code class="Cm">C</code></a></dt>
      <dd><a class="permalink" href="#int8_t"><code class="Li" id="int8_t">int8_t</code></a></dd>
      <dt id="CU"><a class="permalink" href="#CU"><code class="Cm">CU</code></a></dt>
      <dd><a class="permalink" href="#uint8_t"><code class="Li" id="uint8_t">uint8_t</code></a></dd>
      <dt id="I"><a class="permalink" href="#I"><code class="Cm">I</code></a></dt>
      <dd><a class="permalink" href="#int"><code class="Li" id="int">int</code></a></dd>
      <dt id="IK"><a class="permalink" href="#IK"><code class="Cm">IK</code></a>[<var class="Ar">n</var>]</dt>
      <dd>temperature in Kelvin, multiplied by an optional single digit power of
          ten scaling factor: 1 (default) gives deciKelvin, 0 gives Kelvin, 3
          gives milliKelvin</dd>
      <dt id="IU"><a class="permalink" href="#IU"><code class="Cm">IU</code></a></dt>
      <dd><a class="permalink" href="#unsigned"><code class="Li" id="unsigned">unsigned
          int</code></a></dd>
      <dt id="L"><a class="permalink" href="#L"><code class="Cm">L</code></a></dt>
      <dd><a class="permalink" href="#long"><code class="Li" id="long">long</code></a></dd>
      <dt id="LU"><a class="permalink" href="#LU"><code class="Cm">LU</code></a></dt>
      <dd><a class="permalink" href="#unsigned~2"><code class="Li" id="unsigned~2">unsigned
          long</code></a></dd>
      <dt id="Q"><a class="permalink" href="#Q"><code class="Cm">Q</code></a></dt>
      <dd><a class="permalink" href="#quad_t"><code class="Li" id="quad_t">quad_t</code></a></dd>
      <dt id="QU"><a class="permalink" href="#QU"><code class="Cm">QU</code></a></dt>
      <dd><a class="permalink" href="#u_quad_t"><code class="Li" id="u_quad_t">u_quad_t</code></a></dd>
      <dt id="S"><a class="permalink" href="#S"><code class="Cm">S</code></a></dt>
      <dd><a class="permalink" href="#int16_t"><code class="Li" id="int16_t">int16_t</code></a></dd>
      <dt id="SU"><a class="permalink" href="#SU"><code class="Cm">SU</code></a></dt>
      <dd><a class="permalink" href="#uint16_t"><code class="Li" id="uint16_t">uint16_t</code></a></dd>
      <dt id="S,TYPE"><a class="permalink" href="#S,TYPE"><code class="Cm">S,TYPE</code></a></dt>
      <dd><a class="permalink" href="#struct"><code class="Li" id="struct">struct
          TYPE</code></a> structures</dd>
    </dl>
    </div>
  </dd>
  <dt><var class="Fa">descr</var></dt>
  <dd>A pointer to a textual description of the OID.</dd>
  <dt><var class="Fa">label</var></dt>
  <dd>A pointer to an aggregation label for this component of the OID. To make
      it easier to export sysctl data to monitoring systems that support
      aggregations through labels (e.g., Prometheus), this argument can be used
      to attach a label name to an OID. The label acts as a hint that this
      component's name should not be part of the metric's name, but attached to
      the metric as a label instead.
    <p class="Pp">Labels should only be applied to siblings that are
        structurally similar and encode the same type of value, as aggregation
        is of no use otherwise.</p>
  </dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="NODE_VALUE_TYPES"><a class="permalink" href="#NODE_VALUE_TYPES">NODE
  VALUE TYPES</a></h1>
<p class="Pp">Most of the macros and functions used to create sysctl nodes
    export a read-only constant or in-kernel variable whose type matches the
    type of the node's value. For example,
    <a class="permalink" href="#SYSCTL_INT"><code class="Fn" id="SYSCTL_INT">SYSCTL_INT</code></a>()
    reports the raw value of an associated variable of type
    <var class="Vt">int</var>. However, nodes may also export a value that is a
    translation of an internal representation.</p>
<p class="Pp" id="sysctl_msec_to_ticks">The
    <a class="permalink" href="#sysctl_msec_to_ticks"><code class="Fn">sysctl_msec_to_ticks</code></a>()
    handler can be used with <code class="Fn">SYSCTL_PROC</code>() or
    <a class="permalink" href="#SYSCTL_ADD_PROC"><code class="Fn" id="SYSCTL_ADD_PROC">SYSCTL_ADD_PROC</code></a>()
    to export a millisecond time interval. When using this handler, the
    <var class="Fa">arg2</var> parameter points to an in-kernel variable of type
    <var class="Vt">int</var> which stores a tick count suitable for use with
    functions like <a class="Xr">tsleep(9)</a>. The
    <code class="Fn">sysctl_msec_to_ticks</code>() function converts this value
    to milliseconds when reporting the node's value. Similarly,
    <code class="Fn">sysctl_msec_to_ticks</code>() accepts new values in
    milliseconds and stores an equivalent value in ticks to
    <var class="Fa">*arg2</var>. Note that new code should use kernel variables
    of type <var class="Vt">sbintime_t</var> instead of tick counts.</p>
<p class="Pp" id="SYSCTL_ADD_SBINTIME_MSEC">The
    <a class="permalink" href="#SYSCTL_ADD_SBINTIME_MSEC"><code class="Fn">SYSCTL_ADD_SBINTIME_MSEC</code></a>()
    and
    <a class="permalink" href="#SYSCTL_ADD_SBINTIME_USEC"><code class="Fn" id="SYSCTL_ADD_SBINTIME_USEC">SYSCTL_ADD_SBINTIME_USEC</code></a>()
    functions and
    <a class="permalink" href="#SYSCTL_SBINTIME_MSEC"><code class="Fn" id="SYSCTL_SBINTIME_MSEC">SYSCTL_SBINTIME_MSEC</code></a>()
    and
    <a class="permalink" href="#SYSCTL_SBINTIME_USEC"><code class="Fn" id="SYSCTL_SBINTIME_USEC">SYSCTL_SBINTIME_USEC</code></a>()
    macros all create nodes which export an in-kernel variable of type
    <var class="Vt">sbintime_t</var>. These nodes do not export the raw value of
    the associated variable. Instead, they export a 64-bit integer containing a
    count of either milliseconds (the MSEC variants) or microseconds (the USEC
    variants).</p>
<p class="Pp" id="SYSCTL_ADD_TIMEVAL_SEC">The
    <a class="permalink" href="#SYSCTL_ADD_TIMEVAL_SEC"><code class="Fn">SYSCTL_ADD_TIMEVAL_SEC</code></a>()
    function and
    <a class="permalink" href="#SYSCTL_TIMEVAL_SEC"><code class="Fn" id="SYSCTL_TIMEVAL_SEC">SYSCTL_TIMEVAL_SEC</code></a>()
    macro create nodes which export an in-kernel variable of type
    <var class="Vt">struct timeval</var>. These nodes do not export full value
    of the associated structure. Instead, they export a count in seconds as a
    simple integer which is stored in the <var class="Fa">tv_sec</var> field of
    the associated variable. This function and macro are intended to be used
    with variables which store a non-negative interval rather than an absolute
    time. As a result, they reject attempts to store negative values.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="CREATING_ROOT_NODES"><a class="permalink" href="#CREATING_ROOT_NODES">CREATING
  ROOT NODES</a></h1>
<p class="Pp">Sysctl MIBs or OIDs are created in a hierarchical tree. The nodes
    at the bottom of the tree are called root nodes, and have no parent OID. To
    create bottom tree nodes the
    <a class="permalink" href="#SYSCTL_ROOT_NODE"><code class="Fn" id="SYSCTL_ROOT_NODE">SYSCTL_ROOT_NODE</code></a>()
    macro or the
    <a class="permalink" href="#SYSCTL_ADD_ROOT_NODE"><code class="Fn" id="SYSCTL_ADD_ROOT_NODE">SYSCTL_ADD_ROOT_NODE</code></a>()
    function needs to be used. By default all static sysctl node OIDs are global
    and need a
    <a class="permalink" href="#SYSCTL_DECL"><code class="Fn" id="SYSCTL_DECL">SYSCTL_DECL</code></a>()
    statement prior to their
    <a class="permalink" href="#SYSCTL_NODE"><code class="Fn" id="SYSCTL_NODE">SYSCTL_NODE</code></a>()
    definition statement, typically in a so-called header file.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="CREATING_SYSCTL_STRINGS"><a class="permalink" href="#CREATING_SYSCTL_STRINGS">CREATING
  SYSCTL STRINGS</a></h1>
<p class="Pp">Zero terminated character strings sysctls are created either using
    the
    <a class="permalink" href="#SYSCTL_STRING"><code class="Fn" id="SYSCTL_STRING">SYSCTL_STRING</code></a>()
    macro or the
    <a class="permalink" href="#SYSCTL_ADD_STRING"><code class="Fn" id="SYSCTL_ADD_STRING">SYSCTL_ADD_STRING</code></a>()
    function. If the <var class="Fa">len</var> argument is zero, the string
    length is computed at every access to the OID using
    <a class="Xr">strlen(3)</a>. Use the
    <a class="permalink" href="#SYSCTL_CONST_STRING"><code class="Fn" id="SYSCTL_CONST_STRING">SYSCTL_CONST_STRING</code></a>()
    macro or the
    <a class="permalink" href="#SYSCTL_ADD_CONST_STRING"><code class="Fn" id="SYSCTL_ADD_CONST_STRING">SYSCTL_ADD_CONST_STRING</code></a>()
    function to add a sysctl for a constant string.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="CREATING_OPAQUE_SYSCTLS"><a class="permalink" href="#CREATING_OPAQUE_SYSCTLS">CREATING
  OPAQUE SYSCTLS</a></h1>
<p class="Pp">The
    <a class="permalink" href="#SYSCTL_OPAQUE"><code class="Fn" id="SYSCTL_OPAQUE">SYSCTL_OPAQUE</code></a>()
    or
    <a class="permalink" href="#SYSCTL_STRUCT"><code class="Fn" id="SYSCTL_STRUCT">SYSCTL_STRUCT</code></a>()
    macros or the
    <a class="permalink" href="#SYSCTL_ADD_OPAQUE"><code class="Fn" id="SYSCTL_ADD_OPAQUE">SYSCTL_ADD_OPAQUE</code></a>()
    or
    <a class="permalink" href="#SYSCTL_ADD_STRUCT"><code class="Fn" id="SYSCTL_ADD_STRUCT">SYSCTL_ADD_STRUCT</code></a>()
    functions create an OID that handle any chunk of data of the size specified
    by the <var class="Fa">len</var> argument and data pointed to by the
    <var class="Fa">ptr</var> argument. When using the structure version the
    type is encoded as part of the created sysctl.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="CREATING_CUSTOM_SYSCTLS"><a class="permalink" href="#CREATING_CUSTOM_SYSCTLS">CREATING
  CUSTOM SYSCTLS</a></h1>
<p class="Pp">The <code class="Fn">SYSCTL_PROC</code>() macro and the
    <code class="Fn">SYSCTL_ADD_PROC</code>() function create OIDs with the
    specified <span class="Pa">handler</span> function. The handler is
    responsible for handling all read and write requests to the OID. This OID
    type is especially useful if the kernel data is not easily accessible, or
    needs to be processed before exporting.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="CREATING_A_STATIC_SYSCTL"><a class="permalink" href="#CREATING_A_STATIC_SYSCTL">CREATING
  A STATIC SYSCTL</a></h1>
<p class="Pp">Static sysctls are declared using one of the
    <a class="permalink" href="#SYSCTL_BOOL"><code class="Fn" id="SYSCTL_BOOL">SYSCTL_BOOL</code></a>(),
    <a class="permalink" href="#SYSCTL_COUNTER_U64"><code class="Fn" id="SYSCTL_COUNTER_U64">SYSCTL_COUNTER_U64</code></a>(),
    <a class="permalink" href="#SYSCTL_COUNTER_U64_ARRAY"><code class="Fn" id="SYSCTL_COUNTER_U64_ARRAY">SYSCTL_COUNTER_U64_ARRAY</code></a>(),
    <code class="Fn">SYSCTL_INT</code>(),
    <a class="permalink" href="#SYSCTL_INT_WITH_LABEL"><code class="Fn" id="SYSCTL_INT_WITH_LABEL">SYSCTL_INT_WITH_LABEL</code></a>(),
    <a class="permalink" href="#SYSCTL_LONG"><code class="Fn" id="SYSCTL_LONG">SYSCTL_LONG</code></a>(),
    <code class="Fn">SYSCTL_NODE</code>(),
    <a class="permalink" href="#SYSCTL_NODE_WITH_LABEL"><code class="Fn" id="SYSCTL_NODE_WITH_LABEL">SYSCTL_NODE_WITH_LABEL</code></a>(),
    <code class="Fn">SYSCTL_OPAQUE</code>(),
    <code class="Fn">SYSCTL_PROC</code>(),
    <a class="permalink" href="#SYSCTL_QUAD"><code class="Fn" id="SYSCTL_QUAD">SYSCTL_QUAD</code></a>(),
    <code class="Fn">SYSCTL_ROOT_NODE</code>(),
    <a class="permalink" href="#SYSCTL_S8"><code class="Fn" id="SYSCTL_S8">SYSCTL_S8</code></a>(),
    <a class="permalink" href="#SYSCTL_S16"><code class="Fn" id="SYSCTL_S16">SYSCTL_S16</code></a>(),
    <a class="permalink" href="#SYSCTL_S32"><code class="Fn" id="SYSCTL_S32">SYSCTL_S32</code></a>(),
    <a class="permalink" href="#SYSCTL_S64"><code class="Fn" id="SYSCTL_S64">SYSCTL_S64</code></a>(),
    <code class="Fn">SYSCTL_SBINTIME_MSEC</code>(),
    <code class="Fn">SYSCTL_SBINTIME_USEC</code>(),
    <code class="Fn">SYSCTL_STRING</code>(),
    <code class="Fn">SYSCTL_CONST_STRING</code>(),
    <code class="Fn">SYSCTL_STRUCT</code>(),
    <code class="Fn">SYSCTL_TIMEVAL_SEC</code>(),
    <a class="permalink" href="#SYSCTL_U8"><code class="Fn" id="SYSCTL_U8">SYSCTL_U8</code></a>(),
    <a class="permalink" href="#SYSCTL_U16"><code class="Fn" id="SYSCTL_U16">SYSCTL_U16</code></a>(),
    <a class="permalink" href="#SYSCTL_U32"><code class="Fn" id="SYSCTL_U32">SYSCTL_U32</code></a>(),
    <a class="permalink" href="#SYSCTL_U64"><code class="Fn" id="SYSCTL_U64">SYSCTL_U64</code></a>(),
    <a class="permalink" href="#SYSCTL_UINT"><code class="Fn" id="SYSCTL_UINT">SYSCTL_UINT</code></a>(),
    <a class="permalink" href="#SYSCTL_ULONG"><code class="Fn" id="SYSCTL_ULONG">SYSCTL_ULONG</code></a>(),
    <a class="permalink" href="#SYSCTL_UQUAD"><code class="Fn" id="SYSCTL_UQUAD">SYSCTL_UQUAD</code></a>(),
    <a class="permalink" href="#SYSCTL_UMA_CUR"><code class="Fn" id="SYSCTL_UMA_CUR">SYSCTL_UMA_CUR</code></a>()
    or
    <a class="permalink" href="#SYSCTL_UMA_MAX"><code class="Fn" id="SYSCTL_UMA_MAX">SYSCTL_UMA_MAX</code></a>()
    macros.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="CREATING_A_DYNAMIC_SYSCTL"><a class="permalink" href="#CREATING_A_DYNAMIC_SYSCTL">CREATING
  A DYNAMIC SYSCTL</a></h1>
<p class="Pp">Dynamic nodes are created using one of the
    <a class="permalink" href="#SYSCTL_ADD_BOOL"><code class="Fn" id="SYSCTL_ADD_BOOL">SYSCTL_ADD_BOOL</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_COUNTER_U64"><code class="Fn" id="SYSCTL_ADD_COUNTER_U64">SYSCTL_ADD_COUNTER_U64</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_COUNTER_U64_ARRAY"><code class="Fn" id="SYSCTL_ADD_COUNTER_U64_ARRAY">SYSCTL_ADD_COUNTER_U64_ARRAY</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_INT"><code class="Fn" id="SYSCTL_ADD_INT">SYSCTL_ADD_INT</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_LONG"><code class="Fn" id="SYSCTL_ADD_LONG">SYSCTL_ADD_LONG</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_NODE"><code class="Fn" id="SYSCTL_ADD_NODE">SYSCTL_ADD_NODE</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_NODE_WITH_LABEL"><code class="Fn" id="SYSCTL_ADD_NODE_WITH_LABEL">SYSCTL_ADD_NODE_WITH_LABEL</code></a>(),
    <code class="Fn">SYSCTL_ADD_OPAQUE</code>(),
    <code class="Fn">SYSCTL_ADD_PROC</code>(),
    <a class="permalink" href="#SYSCTL_ADD_QUAD"><code class="Fn" id="SYSCTL_ADD_QUAD">SYSCTL_ADD_QUAD</code></a>(),
    <code class="Fn">SYSCTL_ADD_ROOT_NODE</code>(),
    <a class="permalink" href="#SYSCTL_ADD_S8"><code class="Fn" id="SYSCTL_ADD_S8">SYSCTL_ADD_S8</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_S16"><code class="Fn" id="SYSCTL_ADD_S16">SYSCTL_ADD_S16</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_S32"><code class="Fn" id="SYSCTL_ADD_S32">SYSCTL_ADD_S32</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_S64"><code class="Fn" id="SYSCTL_ADD_S64">SYSCTL_ADD_S64</code></a>(),
    <code class="Fn">SYSCTL_ADD_SBINTIME_MSEC</code>(),
    <code class="Fn">SYSCTL_ADD_SBINTIME_USEC</code>(),
    <code class="Fn">SYSCTL_ADD_STRING</code>(),
    <code class="Fn">SYSCTL_ADD_CONST_STRING</code>(),
    <code class="Fn">SYSCTL_ADD_STRUCT</code>(),
    <code class="Fn">SYSCTL_ADD_TIMEVAL_SEC</code>(),
    <a class="permalink" href="#SYSCTL_ADD_U8"><code class="Fn" id="SYSCTL_ADD_U8">SYSCTL_ADD_U8</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_U16"><code class="Fn" id="SYSCTL_ADD_U16">SYSCTL_ADD_U16</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_U32"><code class="Fn" id="SYSCTL_ADD_U32">SYSCTL_ADD_U32</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_U64"><code class="Fn" id="SYSCTL_ADD_U64">SYSCTL_ADD_U64</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_UAUTO"><code class="Fn" id="SYSCTL_ADD_UAUTO">SYSCTL_ADD_UAUTO</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_UINT"><code class="Fn" id="SYSCTL_ADD_UINT">SYSCTL_ADD_UINT</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_ULONG"><code class="Fn" id="SYSCTL_ADD_ULONG">SYSCTL_ADD_ULONG</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_UQUAD"><code class="Fn" id="SYSCTL_ADD_UQUAD">SYSCTL_ADD_UQUAD</code></a>(),
    <a class="permalink" href="#SYSCTL_ADD_UMA_CUR"><code class="Fn" id="SYSCTL_ADD_UMA_CUR">SYSCTL_ADD_UMA_CUR</code></a>()
    or
    <a class="permalink" href="#SYSCTL_ADD_UMA_MAX"><code class="Fn" id="SYSCTL_ADD_UMA_MAX">SYSCTL_ADD_UMA_MAX</code></a>()
    functions. See <a class="Xr">sysctl_remove_oid(9)</a> or
    <a class="Xr">sysctl_ctx_free(9)</a> for more information on how to destroy
    a dynamically created OID.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="CONTROL_FLAGS"><a class="permalink" href="#CONTROL_FLAGS">CONTROL
  FLAGS</a></h1>
<p class="Pp">For most of the above functions and macros, declaring a type as
    part of the access flags is not necessary &#x2014; however, when declaring a
    sysctl implemented by a function, including a type in the access mask is
    required:</p>
<dl class="Bl-tag">
  <dt id="CTLTYPE_NODE"><a class="permalink" href="#CTLTYPE_NODE"><code class="Dv">CTLTYPE_NODE</code></a></dt>
  <dd>This is a node intended to be a parent for other nodes.</dd>
  <dt id="CTLTYPE_INT"><a class="permalink" href="#CTLTYPE_INT"><code class="Dv">CTLTYPE_INT</code></a></dt>
  <dd>This is a signed integer.</dd>
  <dt id="CTLTYPE_STRING"><a class="permalink" href="#CTLTYPE_STRING"><code class="Dv">CTLTYPE_STRING</code></a></dt>
  <dd>This is a nul-terminated string stored in a character array.</dd>
  <dt id="CTLTYPE_S8"><a class="permalink" href="#CTLTYPE_S8"><code class="Dv">CTLTYPE_S8</code></a></dt>
  <dd>This is an 8-bit signed integer.</dd>
  <dt id="CTLTYPE_S16"><a class="permalink" href="#CTLTYPE_S16"><code class="Dv">CTLTYPE_S16</code></a></dt>
  <dd>This is a 16-bit signed integer.</dd>
  <dt id="CTLTYPE_S32"><a class="permalink" href="#CTLTYPE_S32"><code class="Dv">CTLTYPE_S32</code></a></dt>
  <dd>This is a 32-bit signed integer.</dd>
  <dt id="CTLTYPE_S64"><a class="permalink" href="#CTLTYPE_S64"><code class="Dv">CTLTYPE_S64</code></a></dt>
  <dd>This is a 64-bit signed integer.</dd>
  <dt id="CTLTYPE_OPAQUE"><a class="permalink" href="#CTLTYPE_OPAQUE"><code class="Dv">CTLTYPE_OPAQUE</code></a></dt>
  <dd>This is an opaque data structure.</dd>
  <dt id="CTLTYPE_STRUCT"><a class="permalink" href="#CTLTYPE_STRUCT"><code class="Dv">CTLTYPE_STRUCT</code></a></dt>
  <dd>Alias for <code class="Dv">CTLTYPE_OPAQUE</code>.</dd>
  <dt id="CTLTYPE_U8"><a class="permalink" href="#CTLTYPE_U8"><code class="Dv">CTLTYPE_U8</code></a></dt>
  <dd>This is an 8-bit unsigned integer.</dd>
  <dt id="CTLTYPE_U16"><a class="permalink" href="#CTLTYPE_U16"><code class="Dv">CTLTYPE_U16</code></a></dt>
  <dd>This is a 16-bit unsigned integer.</dd>
  <dt id="CTLTYPE_U32"><a class="permalink" href="#CTLTYPE_U32"><code class="Dv">CTLTYPE_U32</code></a></dt>
  <dd>This is a 32-bit unsigned integer.</dd>
  <dt id="CTLTYPE_U64"><a class="permalink" href="#CTLTYPE_U64"><code class="Dv">CTLTYPE_U64</code></a></dt>
  <dd>This is a 64-bit unsigned integer.</dd>
  <dt id="CTLTYPE_UINT"><a class="permalink" href="#CTLTYPE_UINT"><code class="Dv">CTLTYPE_UINT</code></a></dt>
  <dd>This is an unsigned integer.</dd>
  <dt id="CTLTYPE_LONG"><a class="permalink" href="#CTLTYPE_LONG"><code class="Dv">CTLTYPE_LONG</code></a></dt>
  <dd>This is a signed long.</dd>
  <dt id="CTLTYPE_ULONG"><a class="permalink" href="#CTLTYPE_ULONG"><code class="Dv">CTLTYPE_ULONG</code></a></dt>
  <dd>This is an unsigned long.</dd>
</dl>
<p class="Pp">All sysctl types except for new node declarations require one of
    the following flags to be set indicating the read and write disposition of
    the sysctl:</p>
<dl class="Bl-tag">
  <dt id="CTLFLAG_RD"><a class="permalink" href="#CTLFLAG_RD"><code class="Dv">CTLFLAG_RD</code></a></dt>
  <dd>This is a read-only sysctl.</dd>
  <dt id="CTLFLAG_RDTUN"><a class="permalink" href="#CTLFLAG_RDTUN"><code class="Dv">CTLFLAG_RDTUN</code></a></dt>
  <dd>This is a read-only sysctl and tunable which is fetched once from the
      system environment early during module load or system boot.</dd>
  <dt id="CTLFLAG_WR"><a class="permalink" href="#CTLFLAG_WR"><code class="Dv">CTLFLAG_WR</code></a></dt>
  <dd>This is a writable sysctl.</dd>
  <dt id="CTLFLAG_RW"><a class="permalink" href="#CTLFLAG_RW"><code class="Dv">CTLFLAG_RW</code></a></dt>
  <dd>This sysctl is readable and writable.</dd>
  <dt id="CTLFLAG_RWTUN"><a class="permalink" href="#CTLFLAG_RWTUN"><code class="Dv">CTLFLAG_RWTUN</code></a></dt>
  <dd>This is a readable and writeable sysctl and tunable which is fetched once
      from the system environment early during module load or system boot.</dd>
  <dt id="CTLFLAG_NOFETCH"><a class="permalink" href="#CTLFLAG_NOFETCH"><code class="Dv">CTLFLAG_NOFETCH</code></a></dt>
  <dd>In case the node is marked as a tunable using the CTLFLAG_[XX]TUN, this
      flag will prevent fetching the initial value from the system environment.
      Typically this flag should only be used for very early low level system
      setup code, and not by common drivers and modules.</dd>
  <dt id="CTLFLAG_MPSAFE"><a class="permalink" href="#CTLFLAG_MPSAFE"><code class="Dv">CTLFLAG_MPSAFE</code></a></dt>
  <dd>This <a class="Xr">sysctl(9)</a> handler is MP safe. Do not grab Giant
      around calls to this handler. This should only be used for
      <a class="permalink" href="#SYSCTL_PROC"><code class="Fn" id="SYSCTL_PROC">SYSCTL_PROC</code></a>()
      entries.</dd>
</dl>
<p class="Pp">Additionally, any of the following optional flags may also be
    specified:</p>
<dl class="Bl-tag">
  <dt id="CTLFLAG_ANYBODY"><a class="permalink" href="#CTLFLAG_ANYBODY"><code class="Dv">CTLFLAG_ANYBODY</code></a></dt>
  <dd>Any user or process can write to this sysctl.</dd>
  <dt id="CTLFLAG_CAPRD"><a class="permalink" href="#CTLFLAG_CAPRD"><code class="Dv">CTLFLAG_CAPRD</code></a></dt>
  <dd>A process in capability mode can read from this sysctl.</dd>
  <dt id="CTLFLAG_CAPWR"><a class="permalink" href="#CTLFLAG_CAPWR"><code class="Dv">CTLFLAG_CAPWR</code></a></dt>
  <dd>A process in capability mode can write to this sysctl.</dd>
  <dt id="CTLFLAG_SECURE"><a class="permalink" href="#CTLFLAG_SECURE"><code class="Dv">CTLFLAG_SECURE</code></a></dt>
  <dd>This sysctl can be written to only if the effective securelevel of the
      process is &#x2264; 0.</dd>
  <dt id="CTLFLAG_PRISON"><a class="permalink" href="#CTLFLAG_PRISON"><code class="Dv">CTLFLAG_PRISON</code></a></dt>
  <dd>This sysctl can be written to by processes in
    <a class="Xr">jail(2)</a>.</dd>
  <dt id="CTLFLAG_SKIP"><a class="permalink" href="#CTLFLAG_SKIP"><code class="Dv">CTLFLAG_SKIP</code></a></dt>
  <dd>When iterating the sysctl name space, do not list this sysctl.</dd>
  <dt id="CTLFLAG_TUN"><a class="permalink" href="#CTLFLAG_TUN"><code class="Dv">CTLFLAG_TUN</code></a></dt>
  <dd>Advisory flag that a system tunable also exists for this variable. The
      initial sysctl value is fetched once from the system environment early
      during module load or system boot.</dd>
  <dt id="CTLFLAG_DYN"><a class="permalink" href="#CTLFLAG_DYN"><code class="Dv">CTLFLAG_DYN</code></a></dt>
  <dd>Dynamically created OIDs automatically get this flag set.</dd>
  <dt id="CTLFLAG_VNET"><a class="permalink" href="#CTLFLAG_VNET"><code class="Dv">CTLFLAG_VNET</code></a></dt>
  <dd>OID references a VIMAGE-enabled variable.</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="EXAMPLES"><a class="permalink" href="#EXAMPLES">EXAMPLES</a></h1>
<p class="Pp">Sample use of <code class="Fn">SYSCTL_DECL</code>() to declare the
    <var class="Va">security</var> sysctl tree for use by new nodes:</p>
<div class="Bd Pp Bd-indent Li">
<pre>SYSCTL_DECL(_security);</pre>
</div>
<p class="Pp">Examples of integer, opaque, string, and procedure sysctls
  follow:</p>
<div class="Bd Pp Bd-indent Li">
<pre>/*
 * Example of a constant integer value.  Notice that the control
 * flags are CTLFLAG_RD, the variable pointer is SYSCTL_NULL_INT_PTR,
 * and the value is declared.
 */
SYSCTL_INT(_kern, OID_AUTO, hz_max, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, HZ_MAXIMUM,
    &quot;Maximum hz value supported&quot;);

/*
 * Example of a variable integer value.  Notice that the control
 * flags are CTLFLAG_RW, the variable pointer is set, and the
 * value is 0.
 */
static int	doingcache = 1;		/* 1 =&gt; enable the cache */
SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &amp;doingcache, 0,
    &quot;Enable name cache&quot;);

/*
 * Example of a variable string value.  Notice that the control
 * flags are CTLFLAG_RW, that the variable pointer and string
 * size are set.  Unlike newer sysctls, this older sysctl uses a
 * static oid number.
 */
char kernelname[MAXPATHLEN] = &quot;/kernel&quot;;	/* XXX bloat */
SYSCTL_STRING(_kern, KERN_BOOTFILE, bootfile, CTLFLAG_RW,
    kernelname, sizeof(kernelname), &quot;Name of kernel file booted&quot;);

/*
 * Example of an opaque data type exported by sysctl.  Notice that
 * the variable pointer and size are provided, as well as a format
 * string for sysctl(8).
 */
static l_fp pps_freq;	/* scaled frequency offset (ns/s) */
SYSCTL_OPAQUE(_kern_ntp_pll, OID_AUTO, pps_freq, CTLFLAG_RD,
    &amp;pps_freq, sizeof(pps_freq), &quot;I&quot;, &quot;&quot;);

/*
 * Example of a procedure based sysctl exporting string
 * information.  Notice that the data type is declared, the NULL
 * variable pointer and 0 size, the function pointer, and the
 * format string for sysctl(8).
 */
SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING |
    CTLFLAG_RW, NULL, 0, sysctl_kern_timecounter_hardware, &quot;A&quot;,
    &quot;&quot;);</pre>
</div>
<p class="Pp">The following is an example of how to create a new top-level
    category and how to hook up another subtree to an existing static node. This
    example does not use contexts, which results in tedious management of all
    intermediate oids, as they need to be freed later on:</p>
<div class="Bd Pp Bd-indent Li">
<pre>#include &lt;sys/sysctl.h&gt;
 ...
/*
 * Need to preserve pointers to newly created subtrees,
 * to be able to free them later:
 */
static struct sysctl_oid *root1;
static struct sysctl_oid *root2;
static struct sysctl_oid *oidp;
static int a_int;
static char *string = &quot;dynamic sysctl&quot;;
 ...

root1 = SYSCTL_ADD_ROOT_NODE(NULL,
	OID_AUTO, &quot;newtree&quot;, CTLFLAG_RW, 0, &quot;new top level tree&quot;);
oidp = SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(root1),
	OID_AUTO, &quot;newint&quot;, CTLFLAG_RW, &amp;a_int, 0, &quot;new int leaf&quot;);
 ...
root2 = SYSCTL_ADD_NODE(NULL, SYSCTL_STATIC_CHILDREN(_debug),
	OID_AUTO, &quot;newtree&quot;, CTLFLAG_RW, 0, &quot;new tree under debug&quot;);
oidp = SYSCTL_ADD_STRING(NULL, SYSCTL_CHILDREN(root2),
	OID_AUTO, &quot;newstring&quot;, CTLFLAG_RD, string, 0, &quot;new string leaf&quot;);</pre>
</div>
<p class="Pp">This example creates the following subtrees:</p>
<div class="Bd Pp Bd-indent Li">
<pre>debug.newtree.newstring
newtree.newint</pre>
</div>
<p class="Pp" id="Care"><a class="permalink" href="#Care"><i class="Em">Care
    should be taken to free all OIDs once they are no longer needed!</i></a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYSCTL_NAMING"><a class="permalink" href="#SYSCTL_NAMING">SYSCTL
  NAMING</a></h1>
<p class="Pp">When adding, modifying, or removing sysctl names, it is important
    to be aware that these interfaces may be used by users, libraries,
    applications, or documentation (such as published books), and are implicitly
    published application interfaces. As with other application interfaces,
    caution must be taken not to break existing applications, and to think about
    future use of new name spaces so as to avoid the need to rename or remove
    interfaces that might be depended on in the future.</p>
<p class="Pp">The semantics chosen for a new sysctl should be as clear as
    possible, and the name of the sysctl must closely reflect its semantics.
    Therefore the sysctl name deserves a fair amount of consideration. It should
    be short but yet representative of the sysctl meaning. If the name consists
    of several words, they should be separated by underscore characters, as in
    <var class="Va">compute_summary_at_mount</var>. Underscore characters may be
    omitted only if the name consists of not more than two words, each being not
    longer than four characters, as in <var class="Va">bootfile</var>.</p>
<p class="Pp">For boolean sysctls, negative logic should be totally avoided.
    That is, do not use names like <var class="Va">no_foobar</var> or
    <var class="Va">foobar_disable</var>. They are confusing and lead to
    configuration errors. Use positive logic instead:
    <var class="Va">foobar</var>, <var class="Va">foobar_enable</var>.</p>
<p class="Pp">A temporary sysctl node OID that should not be relied upon must be
    designated as such by a leading underscore character in its name. For
    example: <var class="Va">_dirty_hack</var>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
  ALSO</a></h1>
<p class="Pp"><a class="Xr">sysctl(3)</a>, <a class="Xr">sysctl(8)</a>,
    <a class="Xr">device_get_sysctl(9)</a>, <a class="Xr">sysctl_add_oid(9)</a>,
    <a class="Xr">sysctl_ctx_free(9)</a>, <a class="Xr">sysctl_ctx_init(9)</a>,
    <a class="Xr">sysctl_remove_oid(9)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">The <a class="Xr">sysctl(8)</a> utility first appeared in
    <span class="Ux">4.4BSD</span>.
    <code class="Nm">SYSCTL_ADD_CONST_STRING</code> first appeared in
    <span class="Ux">FreeBSD 12.1</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">The <code class="Nm">sysctl</code> implementation originally found
    in <span class="Ux">BSD</span> has been extensively rewritten by
    <span class="An">Poul-Henning Kamp</span> in order to add support for name
    lookups, name space iteration, and dynamic addition of MIB nodes.</p>
<p class="Pp">This man page was written by <span class="An">Robert N. M.
    Watson</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="SECURITY_CONSIDERATIONS"><a class="permalink" href="#SECURITY_CONSIDERATIONS">SECURITY
  CONSIDERATIONS</a></h1>
<p class="Pp">When creating new sysctls, careful attention should be paid to the
    security implications of the monitoring or management interface being
    created. Most sysctls present in the kernel are read-only or writable only
    by the superuser. Sysctls exporting extensive information on system data
    structures and operation, especially those implemented using procedures,
    will wish to implement access control to limit the undesired exposure of
    information about other processes, network connections, etc.</p>
<p class="Pp">The following top level sysctl name spaces are commonly used:</p>
<dl class="Bl-tag">
  <dt id="compat"><var class="Va">compat</var></dt>
  <dd>Compatibility layer information.</dd>
  <dt id="debug"><var class="Va">debug</var></dt>
  <dd>Debugging information. Various name spaces exist under
      <var class="Va">debug</var>.</dd>
  <dt id="hw"><var class="Va">hw</var></dt>
  <dd>Hardware and device driver information.</dd>
  <dt id="kern"><var class="Va">kern</var></dt>
  <dd>Kernel behavior tuning; generally deprecated in favor of more specific
      name spaces.</dd>
  <dt id="machdep"><var class="Va">machdep</var></dt>
  <dd>Machine-dependent configuration parameters.</dd>
  <dt id="net"><var class="Va">net</var></dt>
  <dd>Network subsystem. Various protocols have name spaces under
      <var class="Va">net</var>.</dd>
  <dt id="regression"><var class="Va">regression</var></dt>
  <dd>Regression test configuration and information.</dd>
  <dt id="security"><var class="Va">security</var></dt>
  <dd>Security and security-policy configuration and information.</dd>
  <dt id="sysctl"><var class="Va">sysctl</var></dt>
  <dd>Reserved name space for the implementation of sysctl.</dd>
  <dt id="user"><var class="Va">user</var></dt>
  <dd>Configuration settings relating to user application behavior. Generally,
      configuring applications using kernel sysctls is discouraged.</dd>
  <dt id="vfs"><var class="Va">vfs</var></dt>
  <dd>Virtual file system configuration and information.</dd>
  <dt id="vm"><var class="Va">vm</var></dt>
  <dd>Virtual memory subsystem configuration and information.</dd>
</dl>
</section>
</div>
<table class="foot">
  <tr>
    <td class="foot-date">September 28, 2025</td>
    <td class="foot-os">FreeBSD 15.0</td>
  </tr>
</table>