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diff --git a/static/v10/man2/intro.2 b/static/v10/man2/intro.2 new file mode 100644 index 00000000..9313ccfd --- /dev/null +++ b/static/v10/man2/intro.2 @@ -0,0 +1,271 @@ +.TH INTRO 2 +.de en +.HP +\\$1 \\fL\\$2\\fP \\$3 +.br +.. +.SH NAME +intro, errno \(mi introduction to system calls and error numbers +.SH SYNOPSIS +.B #include <errno.h> +.SH DESCRIPTION +Section 2 +describes the entries into the kernel. +.PP +Calls that deal with file systems refer to directory entries by name. +In order to +.I read +or +.IR write (2) +data on a file, the file must be opened +.RI ( open, +.I pipe, +.IR creat (2)); +an open file is known by a integer called a +.IR "file descriptor" . +Certain open files admit control operations that alter their behavior; +see in particular +.IR ioctl (2), +.IR stream (4), +and +.IR ttyld (4). +.PP +Besides ordinary file systems, which are passive repositories of data, +organized in a hierarchical directory structure, +there are +special file systems \(em virtual constructs with an interface +that mimics an ordinary file system. +In particular, access to files on remote computers is +mediated by the special file system +.IR netfs (8). +Other special file systems support +.IR proc (4) +and +.IR faced (9.5). +.SH SEE ALSO +.IR intro (3) +.SH DIAGNOSTICS +A `Diagnostics' paragraph appears below for each system call +that has an error return. +Unless otherwise stated, the error value is the integer \-1, +and the success value is 0. +Upon an error return, +an error number is assigned to +the external variable +.IR errno . +.I Errno +is not cleared on successful calls, so it should be tested only +after an error has occurred. +.PP +There is a table of messages that describe the errors +and a routine for printing them; +see +.IR perror (3). +The list below gives +the number, the name (as defined in +.BR <errno.h> ), +and the +.I perror +message for each error type. +The reasons for error returns are explained in general terms; +further explanations for less obvious error returns +appear in the writeups of individual system calls. +.en 0 \h'\w'EIO'u' "Error 0 +No error has occurred. +.en 1 EPERM "Not owner +An attempt was made to modify a file in some way forbidden +except to its owner or the super-user, +or an ordinary user attempted to do something +allowed only to the super-user. +.en 2 ENOENT "No such file or directory +A file name was specified +and the file should exist but doesn't, or one +of the directories in a path name does not exist. +.en 3 ESRCH "No such process +The process whose number was given to +.I kill +does not exist, or is already dead. +.en 4 EINTR "Interrupted system call +An asynchronous signal (such as interrupt or quit), +which the user has elected to catch, +occurred during a system call. +If execution is resumed +after processing the signal, +it will appear as if the interrupted system call +returned this error condition. +.en 5 EIO "I/O error +A physical I/O error or timeout occurred during +.IR read , +.I write, +or +.I ioctl. +This error may in some cases be returned +on a call following the one to which it actually applies. +.en 6 ENXIO "No such device or address +I/O on a special file refers to a subdevice which does not +exist, +or beyond the limits of the device. +It may also occur when, for example, a tape drive +is off line or no disk pack is loaded on a drive. +.en 7 E2BIG "Arg list too long +An argument list longer than 16384 bytes +was presented to +.IR exec . +.en 8 ENOEXEC "Exec format error +A request was made to execute a file +which, although it has the appropriate permissions, +does not start with a valid magic number, see +.IR a.out (5). +.en 9 EBADF "Bad file number +A file descriptor referred to no +open file, +or a read (resp. write) request was made to +a file which is open only for writing (resp. reading). +.en 10 ECHILD "No children +In a +.IR wait , +the process had no +living or unwaited-for children. +.en 11 EAGAIN "No more processes +In a +.IR fork , +the system's process table was full +or the user is not allowed to create any more +processes. +.en 12 ENOMEM "Not enough memory +During an +.I exec +or +.I brk, +a program asked for more memory or swap space +than the system is able to supply. +.en 13 EACCES "Permission denied +An attempt was made to access a file in a way forbidden +by the protection system. +.en 14 EFAULT "Bad address +The system encountered a hardware fault in attempting to +access the arguments of a system call. +.en 15 EHASF "Directory not empty +An attempt was made to remove a nonempty directory. +.en 16 EBUSY "In use +An attempt was made to mount a device that was already mounted +(or crashed or was copied in mounted state), +to dismount a device +on which there is an active file +(open file, current directory, mounted-on file, active text segment), +or to remove the current directory of some process. +.en 17 EEXIST "File exists +An existing file was mentioned in an inappropriate context, +e.g. +.IR link . +.en 18 EXDEV "Cross-device link +A link to a file on another device +was attempted. +.en 19 ENODEV "No such device +An attempt was made to apply an inappropriate +system call to a device; +e.g. read a write-only device. +.en 20 ENOTDIR "Not a directory +A non-directory was specified where a directory +is required, +for example in a path name or +as an argument to +.IR chdir . +.en 21 EISDIR "Is a directory +An attempt to write on a directory. +.en 22 EINVAL "Invalid argument +Some invalid argument: +dismounting a non-mounted +device, +mentioning an unknown signal in +.IR signal , +reading or writing a file for which +.I lseek +has generated a negative pointer. +Also set by math functions, see +.IR intro (3). +.en 23 ENFILE "File table overflow +The system's table of open files is full, +and temporarily no more +.I opens +can be accepted. +.en 24 EMFILE "Too many open files +The limit is 128 per process. +.en 25 ENOTTY "Illegal ioctl +The function code mentioned in +.I ioctl +does not apply to the file or device. +.en 26 ETXTBSY "Text file busy +An attempt to execute a pure-procedure +program which is currently open. +Also an attempt to open for writing a pure-procedure +program that is being executed. +.en 27 EFBIG "File too large +The size of a file exceeded the maximum (about +.if t 10\u\s-29\s+2\d +.if n 1.0E9 +bytes). +.en 28 ENOSPC "No space left on device +During a +.I write +to an ordinary file, +there was no free space left on the device. +.en 29 ESPIPE "Illegal seek +An +.I lseek +was issued to a pipe or +other non-seekable device. +.en 30 EROFS "Read-only file system +An attempt to modify a file or directory +was made +on a device mounted read-only. +.en 31 EMLINK "Too many links +An attempt to make more than 32767 links to a file. +.en 32 EPIPE "Broken pipe +A write on a pipe for which there is no process +to read the data, or on a file with insufficient +security clearance. +This condition normally generates a signal; +the error is returned if the signal is ignored. +.en 33 EDOM "Math argument +The argument of a function in the math package (3M) +is out of the domain of the function. +.en 34 ERANGE "Result too large +The value of a function in the math package (3M) +is unrepresentable within machine precision. +.en 35 ELOOP "Link loop +An endless cycle of symbolic links was encountered. +.en 36 ECONC "Concurrency violation +The open was in violation of the concurrent access specified +for the file, +or an attempted IO operation violated a process exclusive (pex) lock. +.en 37 EGREG "It's all Greg's fault +Something went wrong. +.en 38 ELAB "Security label violation +An action which would, if completed, break security rules; see +.IR getplab (2). +.en 39 ENOSYS "No such system call +An attempt to execute a nonexistent or unsupported system call. +.en 40 ENLAB "Out of security labels +A system table for security labels is full: +a trouble similar to +.BR ENFILE . +.en 41 EPRIV "Insufficient privilege +An attempt was made to execute a priviledged system call, or +exercise a privileged feature of a regular system call. +.SH SEE ALSO +.IR perror (3) +.SH BUGS +Device drivers and special file systems may use error codes in +unexpected or unconventional ways; +it is infeasible to list them all. +For example, the crash of a remote computer or the +failure of a communication protocol can produce +.L ENOENT +(no such file or directory) in response to +an attempt to open a file through the network file system. +.br +To avoid publishing duplicates of trivially changed manual pages, +.L ELAB +is not recorded among diagnostics when that would be the only +difference from v9. |