man3/mempcpy.3

   1 .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
   2 .\"
   3 .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
   4 .\" Distributed under GPL
   5 .\" %%%LICENSE_END
   6 .\"
   7 .\" Heavily based on glibc infopages, copyright Free Software Foundation
   8 .\"
   9 .\" aeb, 2003, polished a little
  10 .TH MEMPCPY 3 2015-03-02 "GNU" "Linux Programmer's Manual"
  11 .SH NAME
  12 mempcpy, wmempcpy  \- copy memory area
  13 .SH SYNOPSIS
  14 .nf
  15 .BR "#define _GNU_SOURCE" "         /* See feature_test_macros(7) */"
  16 .br
  17 .B #include <string.h>
  18 .sp
  19 .BI "void *mempcpy(void *" dest ", const void *" src ", size_t " n );
  20 .sp
  21 .BR "#define _GNU_SOURCE" "         /* See feature_test_macros(7) */"
  22 .br
  23 .B #include <wchar.h>
  24 .sp
  25 .BI "wchar_t *wmempcpy(wchar_t *" dest ", const wchar_t *" src ", size_t " n );
  26 .fi
  27 .SH DESCRIPTION
  28 The
  29 .BR mempcpy ()
  30 function is nearly identical to the
  31 .BR memcpy (3)
  32 function.
  33 It copies
  34 .I n
  35 bytes from the object beginning at
  36 .I src
  37 into the object pointed to by
  38 .IR dest .
  39 But instead of returning the value of
  40 .I dest
  41 it returns a pointer to the byte following the last written byte.
  42 .PP
  43 This function is useful in situations where a number of objects
  44 shall be copied to consecutive memory positions.
  45 .PP
  46 The
  47 .BR wmempcpy ()
  48 function is identical but takes
  49 .I wchar_t
  50 type arguments and copies
  51 .I n
  52 wide characters.
  53 .SH RETURN VALUE
  54 .I dest
  55 +
  56 .IR n .
  57 .SH VERSIONS
  58 .BR mempcpy ()
  59 first appeared in glibc in version 2.1.
  60 .SH ATTRIBUTES
  61 For an explanation of the terms used in this section, see
  62 .BR attributes (7).
  63 .TS
  64 allbox;
  65 lbw21 lb lb
  66 l l l.
  67 Interface       Attribute       Value
  68 T{
  69 .BR mempcpy (),
  70 .BR wmempcpy ()
  71 T}      Thread safety   MT-Safe
  72 .TE
  73 .SH CONFORMING TO
  74 This function is a GNU extension.
  75 .SH EXAMPLE
  76 .nf
  77 void *
  78 combine(void *o1, size_t s1, void *o2, size_t s2)
  79 {
  80     void *result = malloc(s1 + s2);
  81     if (result != NULL)
  82         mempcpy(mempcpy(result, o1, s1), o2, s2);
  83     return result;
  84 }
  85 .fi
  86 .SH SEE ALSO
  87 .BR memccpy (3),
  88 .BR memcpy (3),
  89 .BR memmove (3),
  90 .BR wmemcpy (3)