2004-11-03 13:51:07 +00:00
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.\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
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.\"
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\"
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.\" References consulted:
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.\" GNU glibc-2 source code and manual
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.\"
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futimesat.2, mount.2, confstr.3, iconv.3, makedev.3, malloc.3, strcasecmp.3, strcat.3, strcmp.3, strcpy.3, strdup.3, strftime.3, strnlen.3, strpbrk.3, strspn.3, strtok.3, strxfrm.3, sk98lin.4, icmp.7, ipv6.7, packet.7, raw.7, rtnetlink.7, unix.7, x25.7, ldconfig.8, nscd.8: tstamp
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2012-05-10 20:09:28 +00:00
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.TH STRNLEN 3 2012-05-10 "GNU" "Linux Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.SH NAME
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strnlen \- determine the length of a fixed-size string
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.SH SYNOPSIS
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.nf
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.B #include <string.h>
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.sp
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.BI "size_t strnlen(const char *" s ", size_t " maxlen );
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.fi
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2010-09-15 06:55:09 +00:00
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.sp
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.in -4n
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.in
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.sp
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.BR strnlen ():
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faccessat.2, dprintf.3, fexecve.3, fmemopen.3, mbsnrtowcs.3, mkfifoat.3, opendir.3, stpcpy.3, stpncpy.3, strnlen.3, strsignal.3, wcpcpy.3, wcpncpy.3, wcscasecmp.3, wcsdup.3, wcsncasecmp.3, wcsnlen.3, wcsnrtombs.3: ffix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-19 16:57:10 +00:00
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.PD 0
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.ad l
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.RS 4
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.TP 4
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Since glibc 2.10:
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_XOPEN_SOURCE\ >=\ 700 || _POSIX_C_SOURCE\ >=\ 200809L
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.TP
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2010-09-15 06:55:09 +00:00
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Before glibc 2.10:
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_GNU_SOURCE
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faccessat.2, dprintf.3, fexecve.3, fmemopen.3, mbsnrtowcs.3, mkfifoat.3, opendir.3, stpcpy.3, stpncpy.3, strnlen.3, strsignal.3, wcpcpy.3, wcpncpy.3, wcscasecmp.3, wcsdup.3, wcsncasecmp.3, wcsnlen.3, wcsnrtombs.3: ffix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-19 16:57:10 +00:00
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.RE
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.ad
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.PD
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2004-11-03 13:51:07 +00:00
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.SH DESCRIPTION
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2007-05-12 09:06:04 +00:00
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The
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.BR strnlen ()
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confstr.3, strcasecmp.3, strcat.3, strcmp.3, strcpy.3, strdup.3, strftime.3, strlen.3, strnlen.3, strpbrk.3, strspn.3, strtok.3, strxfrm.3: Clarify that these functions operate on bytes, not (wide) characters
Change 'character(s)' to 'byte(s)' to make clear that these
functions operate on bytes, not wide / UTF8 characters.
(POSIX uses 'byte(s)' similarly, to make this point.)
Reported-by: Andries E. Brouwer <Andries.Brouwer@cwi.nl>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2012-05-04 04:15:02 +00:00
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function returns the number of bytes in the string
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gets.3, mbtowc.3, printf.3, puts.3, scanf.3, stpcpy.3, stpncpy.3, strcat.3, strlen.3, strnlen.3, strsep.3, strstr.3, strxfrm.3, utmp.5: Global fix: consistent use of "null byte"
Bring more consistency to the discussion of
"[terminating] null byte"
by writing (at least in the initial use in a page)
"[terminating] null byte ('\0')".
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2011-09-28 04:16:17 +00:00
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pointed to by \fIs\fP, excluding the terminating null bye (\(aq\\0\(aq),
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2008-06-09 15:49:35 +00:00
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but at most \fImaxlen\fP.
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2007-05-12 09:06:04 +00:00
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In doing this,
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.BR strnlen ()
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looks only at the first
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confstr.3, strcasecmp.3, strcat.3, strcmp.3, strcpy.3, strdup.3, strftime.3, strlen.3, strnlen.3, strpbrk.3, strspn.3, strtok.3, strxfrm.3: Clarify that these functions operate on bytes, not (wide) characters
Change 'character(s)' to 'byte(s)' to make clear that these
functions operate on bytes, not wide / UTF8 characters.
(POSIX uses 'byte(s)' similarly, to make this point.)
Reported-by: Andries E. Brouwer <Andries.Brouwer@cwi.nl>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2012-05-04 04:15:02 +00:00
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\fImaxlen\fP bytes at \fIs\fP and never beyond \fIs+maxlen\fP.
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2004-11-03 13:51:07 +00:00
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.SH "RETURN VALUE"
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2007-05-12 09:06:04 +00:00
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The
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.BR strnlen ()
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function returns \fIstrlen(s)\fP, if that is less than
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2008-06-09 15:49:35 +00:00
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\fImaxlen\fP, or \fImaxlen\fP
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gets.3, mbtowc.3, printf.3, puts.3, scanf.3, stpcpy.3, stpncpy.3, strcat.3, strlen.3, strnlen.3, strsep.3, strstr.3, strxfrm.3, utmp.5: Global fix: consistent use of "null byte"
Bring more consistency to the discussion of
"[terminating] null byte"
by writing (at least in the initial use in a page)
"[terminating] null byte ('\0')".
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2011-09-28 04:16:17 +00:00
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if there is no null byte (\(aq\\0\(aq) among the first
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confstr.3, strcasecmp.3, strcat.3, strcmp.3, strcpy.3, strdup.3, strftime.3, strlen.3, strnlen.3, strpbrk.3, strspn.3, strtok.3, strxfrm.3: Clarify that these functions operate on bytes, not (wide) characters
Change 'character(s)' to 'byte(s)' to make clear that these
functions operate on bytes, not wide / UTF8 characters.
(POSIX uses 'byte(s)' similarly, to make this point.)
Reported-by: Andries E. Brouwer <Andries.Brouwer@cwi.nl>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2012-05-04 04:15:02 +00:00
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\fImaxlen\fP bytes pointed to by \fIs\fP.
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2004-11-03 13:51:07 +00:00
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.SH "CONFORMING TO"
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2011-09-09 13:42:08 +00:00
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POSIX.1-2008.
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2004-11-03 13:51:07 +00:00
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.SH "SEE ALSO"
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getresuid.2, intro.2, mremap.2, open.2, poll.2, posix_fadvise.2, pread.2, remap_file_pages.2, setresuid.2, signal.2, splice.2, sync_file_range.2, tee.2, vmsplice.2, INFINITY.3, asprintf.3, assert_perror.3, basename.3, bsd_signal.3, canonicalize_file_name.3, clog10.3, crypt.3, dl_iterate_phdr.3, dlopen.3, dprintf.3, encrypt.3, exp10.3, fcloseall.3, fenv.3, ffs.3, fmemopen.3, fopencookie.3, ftw.3, getdate.3, getline.3, getloadavg.3, getopt.3, getsubopt.3, getutent.3, grantpt.3, hsearch.3, intro.3, lseek64.3, memmem.3, mempcpy.3, mq_receive.3, mq_send.3, posix_fallocate.3, pow10.3, program_invocation_name.3, ptsname.3, putgrent.3, readdir.3, sigset.3, sincos.3, stpcpy.3, stpncpy.3, strchr.3, strfry.3, strnlen.3, strptime.3, strsignal.3, strstr.3, strverscmp.3, swab.3, sysv_signal.3, tsearch.3, unlocked_stdio.3, unlockpt.3, wcpcpy.3, wcpncpy.3, wcsdup.3, wcwidth.3: SEE ALSO: Remove redundant reference to feature_test_macros(7)
Reported-by: Florian Lehmann <flo.lehmann@googlemail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-10-31 05:05:22 +00:00
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.BR strlen (3)
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