man3/strdup.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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  23 .\" References consulted:
  24 .\"     Linux libc source code
  25 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  26 .\"     386BSD man pages
  27 .\" Modified Sun Jul 25 10:41:34 1993 by Rik Faith (faith@cs.unc.edu)
  28 .\" Modified Wed Oct 17 01:12:26 2001 by John Levon <moz@compsoc.man.ac.uk>
  29 .TH STRDUP 3  1993-04-12 "GNU" "Linux Programmer's Manual"
  30 .SH NAME
  31 strdup, strndup, strdupa, strndupa \- duplicate a string
  32 .SH SYNOPSIS
  33 .nf
  34 .B #include <string.h>
  35 .sp
  36 .BI "char *strdup(const char *" s );
  37 .sp
  38 .B #define _GNU_SOURCE
  39 .br
  40 .B #include <string.h>
  41 .sp
  42 .BI "char *strndup(const char *" s ", size_t " n );
  43 .br
  44 .BI "char *strdupa(const char *" s );
  45 .br
  46 .BI "char *strndupa(const char *" s ", size_t " n );
  47 .sp
  48 .fi
  49 .SH DESCRIPTION
  50 The \fBstrdup()\fP function returns a pointer to a new string which
  51 is a duplicate of the string \fIs\fP.  Memory for the new string is
  52 obtained with \fBmalloc\fP(3), and can be freed with \fBfree\fP(3).
  53
  54 The \fBstrndup()\fP function is similar, but only copies at most
  55 \fIn\fP characters. If \fIs\fP is longer than \fIn\fP, only \fIn\fP
  56 characters are copied, and a terminating NUL is added.
  57
  58 \fBstrdupa\fP and \fBstrndupa\fP are similar, but use \fBalloca(3)\fP
  59 to allocate the buffer. They are only available when using the GNU
  60 GCC suite, and suffer from the same limitations described in \fBalloca(3)\fP.
  61
  62 .SH "RETURN VALUE"
  63 The \fBstrdup()\fP function returns a pointer to the duplicated
  64 string, or NULL if insufficient memory was available.
  65 .SH ERRORS
  66 .TP
  67 .B ENOMEM
  68 Insufficient memory available to allocate duplicate string.
  69 .SH "CONFORMING TO"
  70 .\" 4.3BSD-Reno, not (first) BSD 4.3.
  71 SVID 3, BSD 4.3.
  72 \fBstrndup()\fP, \fBstrdupa()\fP, and \fBstrndupa()\fP are GNU extensions.
  73 .SH "SEE ALSO"
  74 .BR alloca (3),
  75 .BR calloc (3),
  76 .BR free (3),
  77 .BR malloc (3),
  78 .BR realloc (3)