man3/stpncpy.3

   1 .\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
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  10 .\" References consulted:
  11 .\"   GNU glibc-2 source code and manual
  12 .\"
  13 .\" Corrected, aeb, 990824
  14 .TH STPNCPY 3  2019-03-06 "GNU" "Linux Programmer's Manual"
  15 .SH NAME
  16 stpncpy \- copy a fixed-size string, returning a pointer to its end
  17 .SH SYNOPSIS
  18 .nf
  19 .B #include <string.h>
  20 .PP
  21 .BI "char *stpncpy(char *" dest ", const char *" src ", size_t " n );
  22 .fi
  23 .PP
  24 .in -4n
  25 Feature Test Macro Requirements for glibc (see
  26 .BR feature_test_macros (7)):
  27 .in
  28 .PP
  29 .BR stpncpy ():
  30 .PD 0
  31 .ad l
  32 .RS 4
  33 .TP 4
  34 Since glibc 2.10:
  35 _POSIX_C_SOURCE\ >=\ 200809L
  36 .TP
  37 Before glibc 2.10:
  38 _GNU_SOURCE
  39 .RE
  40 .ad
  41 .PD
  42 .SH DESCRIPTION
  43 The
  44 .BR stpncpy ()
  45 function copies at most
  46 .I n
  47 characters from the string
  48 pointed to by
  49 .IR src ,
  50 including the terminating null byte (\(aq\e0\(aq),
  51 to the array pointed to by
  52 .IR dest .
  53 Exactly
  54 .I n
  55 characters are written at
  56 .IR dest .
  57 If the length
  58 .I strlen(src)
  59 is smaller than
  60 .IR n ,
  61 the
  62 remaining characters in the array pointed to by
  63 .I dest
  64 are filled
  65 with null bytes (\(aq\e0\(aq),
  66 If the length
  67 .I strlen(src)
  68 is greater than or equal to
  69 .IR n ,
  70 the string pointed to by
  71 .I dest
  72 will
  73 not be null-terminated.
  74 .PP
  75 The strings may not overlap.
  76 .PP
  77 The programmer must ensure that there is room for at least
  78 .I n
  79 characters
  80 at
  81 .IR dest .
  82 .SH RETURN VALUE
  83 .BR stpncpy ()
  84 returns a pointer to the terminating null byte
  85 in
  86 .IR dest ,
  87 or, if
  88 .I dest
  89 is not null-terminated,
  90 .IR dest + n .
  91 .SH ATTRIBUTES
  92 For an explanation of the terms used in this section, see
  93 .BR attributes (7).
  94 .TS
  95 allbox;
  96 lb lb lb
  97 l l l.
  98 Interface       Attribute       Value
  99 T{
 100 .BR stpncpy ()
 101 T}      Thread safety   MT-Safe
 102 .TE
 103 .SH CONFORMING TO
 104 This function was added to POSIX.1-2008.
 105 Before that, it was a GNU extension.
 106 It first appeared in version 1.07 of the GNU C library in 1993.
 107 .SH SEE ALSO
 108 .BR strncpy (3),
 109 .BR wcpncpy (3)