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.\" Copyright (c) 1990, 1991 Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)stdio.3 6.5 (Berkeley) 5/6/91
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.\"
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.\" Converted for Linux, Mon Nov 29 16:07:22 1993, faith@cs.unc.edu
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.\" Modified, 2001-12-26, aeb
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.\"
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.TH STDIO 3 2001-12-26 "" "Linux Programmer's Manual"
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.SH NAME
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stdio \- standard input/output library functions
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.SH SYNOPSIS
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.B #include <stdio.h>
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.sp
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.BI "FILE *" stdin ;
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.br
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.BI "FILE *" stdout ;
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.br
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.BI "FILE *" stderr ;
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.SH DESCRIPTION
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The standard I/O library provides a simple and efficient buffered stream
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I/O interface.
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Input and output is mapped into logical data streams and the
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physical I/O characteristics are concealed.
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The functions and macros are
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listed below; more information is available from the individual man pages.
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.PP
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A stream is associated with an external file (which may be a physical
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device) by
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.I opening
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a file, which may involve creating a new file.
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Creating an existing file
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causes its former contents to be discarded.
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If a file can support positioning requests (such as a disk file,
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as opposed to a terminal) then a
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.I file position indicator
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associated with the stream is positioned at the start of the file (byte
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zero), unless the file is opened with append mode.
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If append mode is used,
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it is unspecified whether the position indicator will be placed at the
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start or the end of the file.
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The position indicator is maintained by
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subsequent reads, writes and positioning requests.
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All input occurs as if the characters were read by successive calls to the
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.BR fgetc (3)
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function; all output takes place as if all characters were written by
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successive calls to the
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.BR fputc (3)
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function.
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.PP
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A file is disassociated from a stream by
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.I closing
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the file.
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Output streams are flushed (any unwritten buffer contents are
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transferred to the host environment) before the stream is disassociated from
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the file.
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The value of a pointer to a
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.I FILE
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object is indeterminate after a file is closed (garbage).
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.PP
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A file may be subsequently reopened, by the same or another program
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execution, and its contents reclaimed or modified (if it can be
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repositioned at the start).
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If the main function returns to its original
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caller, or the
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.BR exit (3)
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function is called, all open files are closed (hence all output streams are
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flushed) before program termination.
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Other methods of program termination,
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such as
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.BR abort (3)
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do not bother about closing files properly.
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.PP
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At program startup, three text streams are predefined and need not be
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opened explicitly:
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.I standard input
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(for reading conventional input),
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.I standard output
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(for writing conventional input), and
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.I standard error
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(for writing diagnostic output).
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These streams are abbreviated
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.IR stdin , stdout
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and
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.IR stderr .
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When opened, the standard error stream is not fully buffered; the standard
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input and output streams are fully buffered if and only if the streams do
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not refer to an interactive device.
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.PP
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Output streams that refer to terminal devices are always line buffered by
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default; pending output to such streams is written automatically whenever
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an input stream that refers to a terminal device is read.
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In cases where a
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large amount of computation is done after printing part of a line on an
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output terminal, it is necessary to
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.BR fflush (3)
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the standard output before going off and computing so that the output will
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appear.
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.PP
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The
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.I stdio
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library is a part of the library
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.B libc
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and routines are automatically loaded as needed by the compilers
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.BR cc (1)
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and
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.BR pc (1).
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The
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SYNOPSIS
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sections of the following manual pages indicate which include files are to
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be used, what the compiler declaration for the function looks like and
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which external variables are of interest.
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.PP
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close.2, epoll_create.2, epoll_ctl.2, fcntl.2, madvise.2, mmap.2, mremap.2, select_tut.2, setgid.2, setuid.2, syscalls.2, vmsplice.2, dlopen.3, fts.3, getpw.3, stdio.3, fd.4, initrd.4, random.4, sd.4, bootparam.7, capabilities.7, cpuset.7, epoll.7, inotify.7, man.7, socket.7, x25.7: Global fix: s/re-/re/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "re-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 17:45:23 +00:00
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The following are defined as macros; these names may not be reused without
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first removing their current definitions with
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.BR #undef :
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.BR BUFSIZ ,
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.BR EOF ,
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.BR FILENAME_MAX ,
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.BR FOPEN_MAX ,
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.BR L_cuserid ,
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.BR L_ctermid ,
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.BR L_tmpnam ,
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.BR NULL ,
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.BR SEEK_END ,
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.BR SEEK_SET ,
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.BR SEEK_CUR ,
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.BR TMP_MAX ,
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.BR clearerr ,
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.BR feof ,
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.BR ferror ,
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.BR fileno ,
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.\" Not on Linux: .BR fropen ,
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.\" Not on Linux: .BR fwopen ,
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.BR getc ,
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.BR getchar ,
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.BR putc ,
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.BR putchar ,
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.BR stderr ,
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.BR stdin ,
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.BR stdout .
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Function versions of the macro functions
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.BR feof ,
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.BR ferror ,
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.BR clearerr ,
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.BR fileno ,
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.BR getc ,
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.BR getchar ,
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.BR putc ,
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and
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.B putchar
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exist and will be used if the macros definitions are explicitly removed.
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intro.1, time.1, _syscall.2, accept.2, brk.2, capget.2, faccessat.2, futimesat.2, gethostname.2, intro.2, ioprio_set.2, kill.2, madvise.2, mlock.2, mount.2, msgget.2, perf_event_open.2, poll.2, readv.2, sched_rr_get_interval.2, sched_setscheduler.2, select.2, select_tut.2, shmget.2, stat.2, timer_create.2, ustat.2, vfork.2, wait.2, alloca.3, atexit.3, catopen.3, crypt.3, dbopen.3, fenv.3, fopen.3, getaddrinfo_a.3, gethostbyname.3, getutent.3, intro.3, login.3, mallopt.3, queue.3, regex.3, sigpause.3, sigsetops.3, stdio.3, strftime.3, strptime.3, sysconf.3, ttyslot.3, undocumented.3, cciss.4, console_codes.4, hpsa.4, initrd.4, intro.4, rtc.4, st.4, tty_ioctl.4, wavelan.4, acct.5, charmap.5, dir_colors.5, hosts.5, intro.5, termcap.5, utmp.5, intro.6, armscii-8.7, boot.7, bootparam.7, capabilities.7, cpuset.7, credentials.7, ddp.7, epoll.7, glob.7, intro.7, ip.7, ipv6.7, iso_8859-1.7, iso_8859-10.7, iso_8859-11.7, iso_8859-13.7, iso_8859-14.7, iso_8859-15.7, iso_8859-16.7, iso_8859-2.7, iso_8859-3.7, iso_8859-4.7, iso_8859-5.7, iso_8859-6.7, iso_8859-7.7, iso_8859-8.7, iso_8859-9.7, koi8-r.7, koi8-u.7, man-pages.7, man.7, math_error.7, netlink.7, numa.7, packet.7, path_resolution.7, pipe.7, pthreads.7, raw.7, rtnetlink.7, signal.7, socket.7, spufs.7, svipc.7, tcp.7, time.7, udp.7, udplite.7, unicode.7, unix.7, uri.7, utf-8.7, x25.7, intro.8: Global fix: use consistent capitalization in .SS headings
Capitalization in .SS sections across pages (and sometimes even
within a single page) is wildly inconsistent. Make it consistent.
Capitalize first word in heading, but otherwise use lower case,
except where English usage (e.g., proper nouns) or programming
language requirements (e.g., identifier names) dictate otherwise.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-02-24 14:08:38 +00:00
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.SS "List of functions"
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.TS
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;
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lb lb
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lb l.
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Function Description
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_
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clearerr check and reset stream status
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fclose close a stream
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fdopen stream open functions
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feof check and reset stream status
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ferror check and reset stream status
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fflush flush a stream
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fgetc get next character or word from input stream
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fgetpos reposition a stream
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fgets get a line from a stream
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fileno return the integer descriptor of the argument stream
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fopen stream open functions
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fprintf formatted output conversion
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fpurge flush a stream
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fputc output a character or word to a stream
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fputs output a line to a stream
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fread binary stream input/output
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freopen stream open functions
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fscanf input format conversion
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fseek reposition a stream
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fsetpos reposition a stream
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ftell reposition a stream
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fwrite binary stream input/output
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getc get next character or word from input stream
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getchar get next character or word from input stream
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gets get a line from a stream
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getw get next character or word from input stream
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mktemp make temporary filename (unique)
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perror system error messages
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printf formatted output conversion
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putc output a character or word to a stream
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putchar output a character or word to a stream
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puts output a line to a stream
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putw output a character or word to a stream
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remove remove directory entry
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rewind reposition a stream
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scanf input format conversion
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setbuf stream buffering operations
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setbuffer stream buffering operations
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setlinebuf stream buffering operations
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setvbuf stream buffering operations
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sprintf formatted output conversion
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sscanf input format conversion
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strerror system error messages
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sys_errlist system error messages
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sys_nerr system error messages
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tempnam temporary file routines
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tmpfile temporary file routines
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tmpnam temporary file routines
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ungetc un-get character from input stream
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vfprintf formatted output conversion
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vfscanf input format conversion
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vprintf formatted output conversion
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vscanf input format conversion
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vsprintf formatted output conversion
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vsscanf input format conversion
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.TE
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.SH "CONFORMING TO"
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The
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.I stdio
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library conforms to C89.
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.SH "SEE ALSO"
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.BR close (2),
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.BR open (2),
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.BR read (2),
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.BR write (2),
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2006-05-17 20:07:21 +00:00
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.BR stdout (3),
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.BR unlocked_stdio (3)
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