diff options
Diffstat (limited to 'lib/libc/stdio/stdio.3')
| -rw-r--r-- | lib/libc/stdio/stdio.3 | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/lib/libc/stdio/stdio.3 b/lib/libc/stdio/stdio.3 new file mode 100644 index 0000000..53320b5 --- /dev/null +++ b/lib/libc/stdio/stdio.3 @@ -0,0 +1,333 @@ +.\" Copyright (c) 1990, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)stdio.3 8.7 (Berkeley) 4/19/94 +.\" $FreeBSD$ +.\" +.Dd March 3, 2009 +.Dt STDIO 3 +.Os +.Sh NAME +.Nm stdio +.Nd standard input/output library functions +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In stdio.h +.Vt FILE *stdin ; +.Vt FILE *stdout ; +.Vt FILE *stderr ; +.Sh DESCRIPTION +The standard +.Tn I/O +library provides a simple and efficient buffered stream +.Tn I/O +interface. +Input and output is mapped into logical data streams +and the physical +.Tn I/O +characteristics are concealed. +The functions and macros are listed +below; more information is available from the individual man pages. +.Pp +A stream is associated with an external file (which may be a physical +device) by +.Em opening +a file, which may involve creating a new file. +Creating an +existing file causes its former contents to be discarded. +If a file can support positioning requests (such as a disk file, as opposed +to a terminal) then a +.Em file position indicator +associated with the stream is positioned at the start of the file (byte +zero), unless the file is opened with append mode. +If append mode +is used, the position indicator will be placed at the end-of-file. +The position indicator is maintained by subsequent reads, writes +and positioning requests. +All input occurs as if the characters +were read by successive calls to the +.Xr fgetc 3 +function; all output takes place as if all characters were +written by successive calls to the +.Xr fputc 3 +function. +.Pp +A file is disassociated from a stream by +.Em closing +the file. +Output streams are flushed (any unwritten buffer contents are transferred +to the host environment) before the stream is disassociated from the file. +The value of a pointer to a +.Dv FILE +object is indeterminate (garbage) after a file is closed. +.Pp +A file may be subsequently reopened, by the same or another program +execution, and its contents reclaimed or modified (if it can be repositioned +at the start). +If the main function returns to its original caller, or +the +.Xr exit 3 +function is called, all open files are closed (hence all output +streams are flushed) before program termination. +Other methods +of program termination may not close files properly and hence +buffered output may be lost. +In particular, +.Xr _exit 2 +does not flush stdio files. +Neither does an exit due to a signal. +Buffers are flushed by +.Xr abort 3 +as required by POSIX, although previous implementations did not. +.Pp +This implementation makes no distinction between +.Dq text +and +.Dq binary +streams. +In effect, all streams are binary. +No translation is performed and no extra padding appears on any stream. +.Pp +At program startup, three streams are predefined and need not be +opened explicitly: +.Bl -bullet -compact -offset indent +.It +.Em standard input +(for reading conventional input), +.It +.Em standard output +(for writing conventional output), and +.It +.Em standard error +(for writing diagnostic output). +.El +These streams are abbreviated +.Dv stdin , stdout +and +.Dv stderr . +Initially, the standard error stream +is unbuffered; the standard input and output streams are +fully buffered if and only if the streams do not refer to +an interactive or +.Dq terminal +device, as determined by the +.Xr isatty 3 +function. +In fact, +.Em all +freshly-opened streams that refer to terminal devices +default to line buffering, and +pending output to such streams is written automatically +whenever such an input stream is read. +Note that this applies only to +.Dq "true reads" ; +if the read request can be satisfied by existing buffered data, +no automatic flush will occur. +In these cases, +or when a large amount of computation is done after printing +part of a line on an output terminal, it is necessary to +.Xr fflush 3 +the standard output before going off and computing so that the output +will appear. +Alternatively, these defaults may be modified via the +.Xr setvbuf 3 +function. +.Pp +The +.Nm +library is a part of the library +.Nm libc +and routines are automatically loaded as needed by the C compiler. +The +.Tn SYNOPSIS +sections of the following manual pages indicate which include files +are to be used, what the compiler declaration for the function +looks like and which external variables are of interest. +.Pp +The following are defined as macros; +these names may not be re-used +without first removing their current definitions with +.Ic #undef : +.Dv BUFSIZ , +.Dv EOF , +.Dv FILENAME_MAX , +.Dv FOPEN_MAX , +.Dv L_ctermid , +.Dv L_cuserid , +.Dv L_tmpnam , +.Dv NULL , +.Dv P_tmpdir , +.Dv SEEK_CUR , +.Dv SEEK_END , +.Dv SEEK_SET , +.Dv TMP_MAX , +.Dv clearerr , +.Dv clearerr_unlocked , +.Dv feof , +.Dv feof_unlocked , +.Dv ferror , +.Dv ferror_unlocked , +.Dv fileno , +.Dv fileno_unlocked , +.Dv fropen , +.Dv fwopen , +.Dv getc , +.Dv getc_unlocked , +.Dv getchar , +.Dv getchar_unlocked , +.Dv putc , +.Dv putc_unlocked , +.Dv putchar , +.Dv putchar_unlocked , +.Dv stderr , +.Dv stdin +and +.Dv stdout . +Function versions of the macro functions +.Dv clearerr , +.Dv clearerr_unlocked , +.Dv feof , +.Dv feof_unlocked , +.Dv ferror , +.Dv ferror_unlocked , +.Dv fileno , +.Dv fileno_unlocked , +.Dv getc , +.Dv getc_unlocked , +.Dv getchar , +.Dv getchar_unlocked , +.Dv putc , +.Dv putc_unlocked , +.Dv putchar , +and +.Dv putchar_unlocked +exist and will be used if the macro +definitions are explicitly removed. +.Sh SEE ALSO +.Xr close 2 , +.Xr open 2 , +.Xr read 2 , +.Xr write 2 +.Sh STANDARDS +The +.Nm +library conforms to +.St -isoC-99 . +.Sh LIST OF FUNCTIONS +.Bl -column "Description" +.It Sy "Function Description" +.It "asprintf formatted output conversion" +.It "clearerr check and reset stream status" +.It "dprintf formatted output conversion" +.It "fclose close a stream" +.It "fdopen stream open functions" +.It "feof check and reset stream status" +.It "ferror check and reset stream status" +.It "fflush flush a stream" +.It "fgetc get next character or word from input stream" +.It "fgetln get a line from a stream" +.It "fgetpos reposition a stream" +.It "fgets get a line from a stream" +.It "fgetwc get next wide character from input stream" +.It "fgetws get a line of wide characters from a stream" +.It "fileno check and reset stream status" +.It "fopen stream open functions" +.It "fprintf formatted output conversion" +.It "fpurge flush a stream" +.It "fputc output a character or word to a stream" +.It "fputs output a line to a stream" +.It "fputwc output a wide character to a stream" +.It "fputws output a line of wide characters to a stream" +.It "fread binary stream input/output" +.It "freopen stream open functions" +.It "fropen open a stream" +.It "fscanf input format conversion" +.It "fseek reposition a stream" +.It "fsetpos reposition a stream" +.It "ftell reposition a stream" +.It "funopen open a stream" +.It "fwide set/get orientation of stream" +.It "fwopen open a stream" +.It "fwprintf formatted wide character output conversion" +.It "fwrite binary stream input/output" +.It "getc get next character or word from input stream" +.It "getchar get next character or word from input stream" +.It "getdelim get a line from a stream" +.It "getline get a line from a stream" +.It "gets get a line from a stream" +.It "getw get next character or word from input stream" +.It "getwc get next wide character from input stream" +.It "getwchar get next wide character from input stream" +.It "mkdtemp create unique temporary directory" +.It "mkstemp create unique temporary file" +.It "mktemp create unique temporary file" +.It "perror system error messages" +.It "printf formatted output conversion" +.It "putc output a character or word to a stream" +.It "putchar output a character or word to a stream" +.It "puts output a line to a stream" +.It "putw output a character or word to a stream" +.It "putwc output a wide character to a stream" +.It "putwchar output a wide character to a stream" +.It "remove remove directory entry" +.It "rewind reposition a stream" +.It "scanf input format conversion" +.It "setbuf stream buffering operations" +.It "setbuffer stream buffering operations" +.It "setlinebuf stream buffering operations" +.It "setvbuf stream buffering operations" +.It "snprintf formatted output conversion" +.It "sprintf formatted output conversion" +.It "sscanf input format conversion" +.It "strerror system error messages" +.It "swprintf formatted wide character output conversion" +.It "sys_errlist system error messages" +.It "sys_nerr system error messages" +.It "tempnam temporary file routines" +.It "tmpfile temporary file routines" +.It "tmpnam temporary file routines" +.It "ungetc un-get character from input stream" +.It "ungetwc un-get wide character from input stream" +.It "vasprintf formatted output conversion" +.It "vdprintf formatted output conversion" +.It "vfprintf formatted output conversion" +.It "vfscanf input format conversion" +.It "vfwprintf formatted wide character output conversion" +.It "vprintf formatted output conversion" +.It "vscanf input format conversion" +.It "vsnprintf formatted output conversion" +.It "vsprintf formatted output conversion" +.It "vsscanf input format conversion" +.It "vswprintf formatted wide character output conversion" +.It "vwprintf formatted wide character output conversion" +.It "wprintf formatted wide character output conversion" +.El +.Sh BUGS +The standard buffered functions do not interact well with certain other +library and system functions, especially +.Xr vfork 2 . |
