2004-11-03 13:51:07 +00:00
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.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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2007-04-12 22:42:49 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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2007-04-12 22:42:49 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" References consulted:
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.\" Linux libc source code
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.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
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.\" 386BSD man pages
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.\" Modified Sun Jul 25 10:41:34 1993 by Rik Faith (faith@cs.unc.edu)
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.\" Modified Wed Oct 17 01:12:26 2001 by John Levon <moz@compsoc.man.ac.uk>
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chdir.2, chmod.2, chown.2, gethostname.2, getsid.2, pread.2, setpgid.2, sigaltstack.2, truncate.2, wait.2, dirfd.3, getsubopt.3, mkdtemp.3, mkstemp.3, siginterrupt.3, strdup.3: tstamp
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-26 15:43:00 +00:00
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.TH STRDUP 3 2010-09-26 "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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strdup, strndup, strdupa, strndupa \- duplicate a 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 "char *strdup(const char *" s );
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.sp
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.BI "char *strndup(const char *" s ", size_t " n );
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.br
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.BI "char *strdupa(const char *" s );
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.br
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.BI "char *strndupa(const char *" s ", size_t " n );
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.fi
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2007-07-08 12:11:40 +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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2010-09-15 06:51:37 +00:00
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.PD 0
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2010-09-18 03:29:52 +00:00
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.ad l
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2007-07-08 12:11:40 +00:00
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.sp
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.BR strdup ():
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2010-09-18 03:29:52 +00:00
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.RS 4
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_SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
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brk.2, chroot.2, vfork.2, ecvt.3, gcvt.3, getcwd.3, getpass.3, mktemp.3, posix_memalign.3, strdup.3, ttyslot.3, ualarm.3, usleep.3: ffix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-26 15:46:36 +00:00
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_XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
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chdir.2, chmod.2, chown.2, gethostname.2, getsid.2, pread.2, setpgid.2, sigaltstack.2, stat.2, truncate.2, wait.2, dirfd.3, getsubopt.3, mkdtemp.3, mkstemp.3, siginterrupt.3, strdup.3: Simplify feature test macro requirements
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-26 15:16:57 +00:00
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.br
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|| /* Since glibc 2.12: */ _POSIX_C_SOURCE\ >=\ 200809L
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2010-09-18 03:29:52 +00:00
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.RE
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.PP
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2010-09-15 06:51:37 +00:00
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.BR strndup ():
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.RS 4
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.TP 4
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Since glibc 2.10:
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brk.2, chroot.2, faccessat.2, fchmodat.2, fchownat.2, fstatat.2, futimesat.2, getdtablesize.2, getpagesize.2, getsid.2, linkat.2, mkdirat.2, mknodat.2, openat.2, pread.2, readlinkat.2, renameat.2, setpgid.2, sigaltstack.2, symlinkat.2, sync.2, timer_create.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, unlinkat.2, utimensat.2, vfork.2, acosh.3, asinh.3, atanh.3, dirfd.3, dprintf.3, ecvt.3, expm1.3, fexecve.3, fmemopen.3, gcvt.3, getcwd.3, gethostid.3, getpass.3, getsubopt.3, getw.3, mbsnrtowcs.3, mkfifoat.3, mkstemp.3, mktemp.3, opendir.3, posix_memalign.3, rint.3, siginterrupt.3, stpcpy.3, stpncpy.3, strdup.3, strerror.3, strnlen.3, strsignal.3, strtol.3, strtoul.3, ualarm.3, usleep.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 06:02:38 +00:00
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POSIX_C_SOURCE\ >=\ 200809L || _XOPEN_SOURCE\ >=\ 700
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2010-09-15 06:51:37 +00:00
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.TP
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Before glibc 2.10:
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_GNU_SOURCE
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.RE
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.PP
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2007-07-08 12:11:40 +00:00
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.BR strdupa (),
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.BR strndupa ():
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_GNU_SOURCE
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2010-09-18 03:29:52 +00:00
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.ad
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2010-09-15 06:51:37 +00:00
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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 strdup ()
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function returns a pointer to a new string which
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2007-04-24 16:44:51 +00:00
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is a duplicate of the string \fIs\fP.
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Memory for the new string is
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2007-05-12 09:06:04 +00:00
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obtained with
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.BR malloc (3),
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and can be freed with
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.BR free (3).
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2004-11-03 13:51:07 +00:00
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2007-05-12 09:06:04 +00:00
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The
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.BR strndup ()
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function is similar, but only copies at most
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2007-04-12 22:42:49 +00:00
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\fIn\fP characters.
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If \fIs\fP is longer than \fIn\fP, only \fIn\fP
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2008-06-09 15:49:35 +00:00
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characters are copied, and a terminating null byte (\(aq\\0\(aq) is added.
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2004-11-03 13:51:07 +00:00
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2007-05-12 09:06:04 +00:00
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.BR strdupa ()
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and
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.BR strndupa ()
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are similar, but use
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.BR alloca (3)
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2007-04-12 22:42:49 +00:00
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to allocate the buffer.
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They are only available when using the GNU
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2007-05-12 09:06:04 +00:00
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GCC suite, and suffer from the same limitations described in
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.BR alloca (3).
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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 strdup ()
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function returns a pointer to the duplicated
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2004-11-03 13:51:07 +00:00
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string, or NULL if insufficient memory was available.
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.SH ERRORS
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.TP
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.B ENOMEM
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Insufficient memory available to allocate duplicate string.
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.SH "CONFORMING TO"
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2005-07-18 15:05:56 +00:00
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.\" 4.3BSD-Reno, not (first) 4.3BSD.
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2006-08-03 13:57:30 +00:00
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.BR strdup ()
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conforms to SVr4, 4.3BSD, POSIX.1-2001.
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2007-05-12 09:06:04 +00:00
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.BR strndup (),
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.BR strdupa (),
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and
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.BR strndupa ()
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are GNU extensions.
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2004-11-03 13:51:07 +00:00
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.SH "SEE ALSO"
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.BR alloca (3),
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.BR calloc (3),
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.BR free (3),
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.BR malloc (3),
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2006-02-09 20:57:44 +00:00
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.BR realloc (3),
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index.3, stpcpy.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strdup.3, strfry.3, strpbrk.3, strsep.3, strspn.3, strstr.3, strtok.3, strxfrm.3: SEE ALSO: Add reference to string(3)
The idea here is to provide a route to discover other
string functions.
Reported-by: Mark Hills <mark@pogo.org.uk>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-12 14:39:58 +00:00
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.BR string (3),
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2007-07-08 12:11:40 +00:00
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.BR wcsdup (3)
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