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 .B #include <string.h>
  17 .PP
  18 .BI "void *mempcpy(void *" dest ", const void *" src ", size_t " n );
  19
  20 .BR "#define _GNU_SOURCE" "         /* See feature_test_macros(7) */"
  21 .B #include <wchar.h>
  22 .PP
  23 .BI "wchar_t *wmempcpy(wchar_t *" dest ", const wchar_t *" src ", size_t " n );
  24 .fi
  25 .SH DESCRIPTION
  26 The
  27 .BR mempcpy ()
  28 function is nearly identical to the
  29 .BR memcpy (3)
  30 function.
  31 It copies
  32 .I n
  33 bytes from the object beginning at
  34 .I src
  35 into the object pointed to by
  36 .IR dest .
  37 But instead of returning the value of
  38 .I dest
  39 it returns a pointer to the byte following the last written byte.
  40 .PP
  41 This function is useful in situations where a number of objects
  42 shall be copied to consecutive memory positions.
  43 .PP
  44 The
  45 .BR wmempcpy ()
  46 function is identical but takes
  47 .I wchar_t
  48 type arguments and copies
  49 .I n
  50 wide characters.
  51 .SH RETURN VALUE
  52 .I dest
  53 +
  54 .IR n .
  55 .SH VERSIONS
  56 .BR mempcpy ()
  57 first appeared in glibc in version 2.1.
  58 .SH ATTRIBUTES
  59 For an explanation of the terms used in this section, see
  60 .BR attributes (7).
  61 .TS
  62 allbox;
  63 lbw21 lb lb
  64 l l l.
  65 Interface       Attribute       Value
  66 T{
  67 .BR mempcpy (),
  68 .BR wmempcpy ()
  69 T}      Thread safety   MT-Safe
  70 .TE
  71 .SH CONFORMING TO
  72 This function is a GNU extension.
  73 .SH EXAMPLE
  74 .EX
  75 void *
  76 combine(void *o1, size_t s1, void *o2, size_t s2)
  77 {
  78     void *result = malloc(s1 + s2);
  79     if (result != NULL)
  80         mempcpy(mempcpy(result, o1, s1), o2, s2);
  81     return result;
  82 }
  83 .EE
  84 .SH SEE ALSO
  85 .BR memccpy (3),
  86 .BR memcpy (3),
  87 .BR memmove (3),
  88 .BR wmemcpy (3)