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Diffstat (limited to 'static/unix-v10/man3/ios.3')
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1 files changed, 384 insertions, 0 deletions
diff --git a/static/unix-v10/man3/ios.3 b/static/unix-v10/man3/ios.3 new file mode 100644 index 00000000..9176eb79 --- /dev/null +++ b/static/unix-v10/man3/ios.3 @@ -0,0 +1,384 @@ +. \"ident "%W%" +. \"Copyright (c) 1984 AT&T +. \"All Rights Reserved +. \"THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T +. \"The copyright notice above does not evidence any +. \"actual or intended publication of such source code. +.TH IOSTREAM 3I+ "C++ Stream Library" " " +.SH NAME +ios \- input/output formatting +.SH SYNOPSIS +.nf +.ta1i 2i +.ft B +#include <iostream.h> + +struct fmtinfo { + ostream* tie; + short convbase; + short width; + short precision; + char fill; + char ladjust; + char showbase; + char skip; + char floatfmt; +}; + +class ios { +public: + enum io_state { goodbit=0, eofbit, failbit, badbit }; + enum open_mode { in, out, ate, app }; + enum seek_dir { beg, cur, end }; +public: + ios(streambuf* b); + + int bad(); + void clear(state_value i = _good); + int convbase(); + void convbase(int i); + int eof(); + int fail(); + char fill(); + void fill(char c); + char floatfmt(); + void floatfmt(char c); + fmtinfo fmt(); + void fmt(fmtinfo& info); + int ladjust(); + void ladjust(int a); + int good(); + int operator!(); + operator int(); + int popfmt(); + int precision(); + void precision(int i); + void pushfmt(); + streambuf* rdbuf(); + int rdstate(); + int showbase(); + void showbase(int i); + int skip(); + int skip(int i); + void sync_with_stdio(); + streampos tellg(); + ostream* tie(); + ostream* tie(ostream* iosp); + int width(); + void width(int i); + + ios& operator<<(ios& (*)(ios&)); + ios& operator>>(ios& (*)(ios&)); +private: + iostream(iostream&) ; + iostream& operator=(iostream&) ; +}; + +class ios_withassign : ios { + ios_withassign(); + ios& operator=(ios&); + ios& operator=(streambuf*); +} ; + +ios& dec(ios& i) ; +ios& hex(ios& i) ; +ios& oct(ios& i) ; +ios& popfmt(ios& i) ; +ios& pushfmt(ios& i) ; +.fi +.ft R +.SH DESCRIPTION +The stream classes derived from \f(CWios\fRs +provide a high level interface that +supports transferring +formatted and unformatted information into and out of +\f(CWstreambuf\fRs. +.PP +In the following assume: +.br +\(em \fBs\fR is an \f(CWios\fR. +.br +\(em \fBswa\fR is an \f(CWios_withassign\fR. +.br +\(em \fBsp\fR is a \f(CWios*\fR. +.br +\(em \fBi\fR and \fBn\fR are \f(CWint\fR. +.br +\(em \fBc\fR is a \f(CWchar\fR. +.br +\(em \fBosp\fR is an \f(CWostream*\fR. +.br +\(em \fBsb\fR is a \f(CWstreambuf*\fR. +.br +\(em \fBpos\fR is a \f(CWstreampos\fR. +.br +\(em \fBoff\fR is a \f(CWstreamoff\fR. +.br +\(em \fBinfo\fR is a \f(CWformatinfo\fR. +.br +\(em \fBdir\fR is a \f(CWseek_dir\fR. +.br +\(em \fBmode\fR is a \f(CWseek_dir\fR. +.br +\(em \fBfct\fR is a function with type \f(CWios& (*)(ios&)\fR. +.PP +Constructors and assignment: +.TP +\fBios(sb)\fR +\fBsb\fR becomes the \f(CWstreambuf\fR associated with the +constructed \fBios\fR. This association is fixed for +the life of the \f(CWios\fR. If \fBsb\fR is null the effect is +undefined. +.TP +\fBios_withassign()\fR +Uninitialized variable. +.sp +.nf +.in -.5i +\fBios(ios&)\fR +\fBios=ios\fR +.in +.fi +Copying of \f(CWios\fR's is not in general +well defined and the constructor and assignment operators +are made private so that the compiler will complain about attempts to +do so. Usually what is desired +is copying of pointers to \f(CWiostream\fRs. +.TP +swa=sb +Associates \fBsb\fR with \fBswa\fR and initializes the entire +state of +\fBswa\fR. +.TP +swa=s +Associates \fBs->rdbuf()\fR with \fBswa\fR and +initializes the entire state of +\fBswa\fR. +.PP +An \fBios\fR has an internal error state (which is a collection +of the bits declared as \f(CWio_state\fRs). Members related +to the error state: +.RS +.TP +\fBi=s.rdstate()\fR +Returns the current error state. +.TP +\fBs.clear(i)\fR +Stores \fBi\fR as the error state. If \fBi\fR is zero +this clears all bits. To set a bit without clearing previously +set bits requires something like \fBs.clear(badbit|s.rdstate())\fR. +.TP +\fBi=s\fR +The \f(CWint\fR conversion operator is non-zero if \f(CWbadbit\fR or +\f(CWfailbit\fR is set in the error state. +.TP +\fBi=s.good()\fR +Non-zero if the error state has no bits set. +.TP +\fBi=s.eof()\fR +Non-zero if \f(CWeofbit\fR is set in the error state. Normally this +bit is set when an end of file has been encountered doing extraction. +.TP +\fBi=s.fail()\fR +Non-zero if either \f(CWbadbit\fR or \f(CWfailbit\fR are set in the +error state. Normally this indicates that some operation has failed. +.TP +\fBi=s.bad()\fR +Non-zero if \fBbadbit\fR is set in the error state. +Normally this indicates +that some operation on \fBs.rdbuf()\fR has failed. +.RE +.PP +An \f(CWios\fR has a collection of format state variables +that are used by input and output operations to control the +details of formatting operations. Otherwise their values +have no particular effect and they may be set and examined arbitrarily +by user code. +.RS +.TP +\fBs.convbase(i)\fR +Sets the "conversion base" format state variable to \fBi\fR. +.TP +\fBi=s.convbase()\fR +Returns the "conversion base" format state variable. +.TP +\fBs.fill(c)\fR +Sets the "fill character" format state variable to \fBc\fR. +.TP +\fBc=s.fill()\fR +Returns the "fill character" format state variable. +.TP +\fBs.fill(c)\fR +Sets the "fill character" format state variable to \fBc\fR. +.TP +\fBc=s.fill()\fR +Returns the "fill character" format state variable. +.TP +\fBs.floatfmt(c)\fR +Sets the "floating format" format state variable to \fBc\fR. +.TP +\fBc=s.floatfmt()\fR +Returns the "floating format" format state variable. +.TP +\fBs.ladjust(i)\fR +Sets the "left adjustment" format state variable to \fBi\fR. +.TP +\fBi=s.ladjust()\fR +Returns the "left adjustment" format state variable. +.TP +\fBs.precision(i)\fR +Sets the "precision" format state variable to \fBi\fR. +.TP +\fBi=s.precision()\fR +Returns the "precision" format state variable. +.TP +\fBs.showbase(i)\fR +Sets the "show explicit base" format state variable to \fBi\fR. +.TP +\fBi=s.showbase()\fR +Returns the "show explicit base" format state variable. +.TP +\fBsp=s.skip(sp)\fR +Sets the "skip whitespace" format state variable to \fBsp\fP. +.TP +\fBsp=s.skip()\fR +Returns the "skip whitespace" format state variable. +.TP +\fBosp=s.tie(osp)\fR +Sets the "tie" format state variable \fBsp\fP. +.TP +\fBosp=s.tie()\fR +Returns the "tie" format state variable. +.TP +\fBs.width(i)\fR +Sets the "field width" format state variable to \fBi\fP. +.TP +\fBi=s.width()\fR +Returns the "field width" format state variable. +.TP +\fBs.fmt(info)\fR +Sets the collection of all format state variables to \fBinfo\fP in +a single operation. +.TP +\fBinfo=s.fmt()\fR +Returns the collection of all format state variables in +a single operation. +.TP +\fBs.pushfmt()\fR +Pushes a \f(CWformatinfo\fR structure onto a (dynamically allocated) +stack associated with \fBs\fR. This copies the current +values of format state variables without changing them. +.TP +\fBi=s.popfmt()\fR +Pops the topmost \f(CWformatinfo\fR from the stack associated with +\fBs\fR and sets the format state variables accordingly. Normally +\fBi\fR is non-zero, but it will be zero if the stack is empty +(i.e., more \fBpopfmt\fR than \fBpushfmt\fR operations have been +performed. +.RE +.PP +Other members: +.TP +\fBsb=s.rdbuf()\fR +Returns a pointer to the \f(CWstreambuf\fR associated with +\fBs\fR when \fBs\fR was constructed. +.TP +\fB((ios*)0)->sync_with_stdio()\fR +Solves problems that arise when mixing stdio and +iostreams. The first time it is called it will reset the +standard iostreams (\f(CWinstream\fR, \f(CWoutstream\fR, \f(CWerrstream\fR, +\f(CWlogstream\fR) to be streams +using \f(CWstdiobuf\fRs. +After that input and output using these streams may +be mixed with input and output using the corresponding \f(CWFILE\fRs and +will be properly synchronized. +.RE +.PP +Convenient manipulators (functions that take an \f(CWios&\fR +and return their argument). +.TP +\fBios<<dec +.in -.5i +.br +.nf +\fBios<<dec +\fBios>>dec\fR +.fi +.in +Sets the convbase to 10. +.sp +.nf +.in -.5i +\fBios<<hex +\fBios>>hex\fR +.in +Sets the convbase to 16. +.sp +.nf +.in -.5i +\fBios<<oct +\fBios>>oct\fR +.fi +.in +Sets the convbase to 8. +.sp +.nf +.in -.5i +\fBios<<popfmt +\fBios>>popfmt\fR +.fi +.in +Does \fBs.popfmt()\fR +.in -.5i +.sp +.nf +\fBios<<pushfmt +\fBios>>pushfmt\fR +.fi +.in +Does \fBs.pushfmt()\fR +.PP +The \f(CWstreambuf\fR associated with an \f(CWios\fR may be manipulated +by other methods than through \f(CWios\fR. For example, characters may +be stored in a queuelike \f(CWstreambuf\fR through an \f(CWostream\fR +while they are being fetched through an \f(CWistream\fR. +Or for efficiency some +part of a program may choose to do \f(CWstreambuf\fR gets +directly rather than through the \f(CWios\fR. +In most cases +the program does not have to worry about this possibility, because +an \f(CWios\fR never saves information about the internal state +of a \f(CWstreambuf\fR. For example if the \f(CWstreambuf\fR is +repostitioned between extraction operations the extraction (input) +will proceed normally. +.SH CAVEATS +.PP +The effect of \fBios.sync_with_stdio()\fR +does not depend on \fBios\fR. +\fBsync_with_stdio\fR ought +to be a global function but it is a member of \fBiostream\fR to +avoid name space pollution. +The need for \fBsync_with_stdio\fR is a wart. The old stream +package did this as a default, but in the iostream package +unbuffered \f(CWstdiobuf\fRs are too inefficient to be the default. +.PP +The stream package had a constructor that took a \fBFILE*\fR argument. +This is now replaced by \f(CWstdiostream\fR. +It is not declared even as an obsolete form to avoid +having \f(CWiostream.h\fR +depend on \f(CWstdio.h\fR. +.PP +The old stream package allowed copying of streams. This is disallowed +by the iostream package. Old code using copying can usually be +rewritten to use pointers and copy pointers. +.PP +For compatibility with the old stream package, the versions of +.I tie +and +.I skip +that set the state variables also return the old value. +.SH SEE ALSO +IOS.INTRO(3C++) +streambuf(3C++) +istream(3C++) +ostream(3C++) |