string/FreeBSD/strdup.3

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  28 .\"     @(#)strdup.3    8.1 (Berkeley) 6/9/93
  29 .\" $FreeBSD: src/lib/libc/string/strdup.3,v 1.15 2009/04/07 13:42:53 trasz Exp $
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  31 .Dd December 5, 2008
  32 .Dt STRDUP 3
  33 .Os
  34 .Sh NAME
  35 .Nm strdup ,
  36 .Nm strndup
  37 .Nd save a copy of a string
  38 .Sh LIBRARY
  39 .Lb libc
  40 .Sh SYNOPSIS
  41 .In string.h
  42 .Ft char *
  43 .Fo strdup
  44 .Fa "const char *s1"
  45 .Fc
  46 .Ft char *
  47 .Fo strndup
  48 .Fa "const char *s1"
  49 .Fa "size_t n"
  50 .Fc
  51 .Sh DESCRIPTION
  52 The
  53 .Fn strdup
  54 function
  55 allocates sufficient memory for a copy
  56 of the string
  57 .Fa s1 ,
  58 does the copy, and returns a pointer to it.
  59 The pointer may subsequently be used as an
  60 argument to the function
  61 .Xr free 3 .
  62 .Pp
  63 If insufficient memory is available, NULL is returned and
  64 .Va errno
  65 is set to
  66 .Er ENOMEM .
  67 .Pp
  68 The
  69 .Fn strndup
  70 function copies at most
  71 .Fa n
  72 characters from the string
  73 .Fa s1
  74 always
  75 .Dv NUL
  76 terminating the copied string.
  77 .Sh SEE ALSO
  78 .Xr free 3 ,
  79 .Xr malloc 3
  80 .Sh HISTORY
  81 The
  82 .Fn strdup
  83 function first appeared in
  84 .Bx 4.4 .
  85 The
  86 .Fn strndup
  87 function was added in
  88 .Fx 7.2 .