man3/wcstombs.3

   1 .\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
   2 .\"
   3 .\" This is free documentation; you can redistribute it and/or
   4 .\" modify it under the terms of the GNU General Public License as
   5 .\" published by the Free Software Foundation; either version 2 of
   6 .\" the License, or (at your option) any later version.
   7 .\"
   8 .\" References consulted:
   9 .\"   GNU glibc-2 source code and manual
  10 .\"   Dinkumware C library reference http://www.dinkumware.com/
  11 .\"   OpenGroup's Single Unix specification http://www.UNIX-systems.org/online.html
  12 .\"   ISO/IEC 9899:1999
  13 .\"
  14 .TH WCSTOMBS 3  1999-07-25 "GNU" "Linux Programmer's Manual"
  15 .SH NAME
  16 wcstombs \- convert a wide character string to a multibyte string
  17 .SH SYNOPSIS
  18 .nf
  19 .B #include <stdlib.h>
  20 .sp
  21 .BI "size_t wcstombs(char *" dest ", const wchar_t *" src ", size_t " n );
  22 .fi
  23 .SH DESCRIPTION
  24 If \fIdest\fP is not a NULL pointer, the \fBwcstombs\fP() function converts
  25 the wide-character string \fIsrc\fP to a multibyte string starting at
  26 \fIdest\fP. At most \fIn\fP bytes are written to \fIdest\fP. The conversion
  27 starts in the initial state. The conversion can stop for three reasons:
  28 .PP
  29 1. A wide character has been encountered that can not be represented as a
  30 multibyte sequence (according to the current locale). In this case
  31 (size_t)(\-1) is returned.
  32 .PP
  33 2. The length limit forces a stop. In this case the number of bytes written to
  34 \fIdest\fP is returned, but the shift state at this point is lost.
  35 .PP
  36 3. The wide-character string has been completely converted, including the
  37 terminating L'\\0'. In this case the conversion ends in the initial state.
  38 The number of bytes written to \fIdest\fP, excluding the terminating '\\0'
  39 byte, is returned.
  40 .PP
  41 The programmer must ensure that there is room for at least \fIn\fP bytes
  42 at \fIdest\fP.
  43 .PP
  44 If \fIdest\fP is NULL, \fIn\fP is ignored, and the conversion proceeds as
  45 above, except that the converted bytes are not written out to memory, and that
  46 no length limit exists.
  47 .PP
  48 In order to avoid the case 2 above, the programmer should make sure \fIn\fP
  49 is greater or equal to \fIwcstombs(NULL,src,0)+1\fP.
  50 .SH "RETURN VALUE"
  51 The \fBwcstombs\fP() function returns the number of bytes that make up the
  52 converted part of multibyte sequence, not including the terminating null byte.
  53 If a wide character was encountered which could not be converted, (size_t)(\-1)
  54 is returned.
  55 .SH "CONFORMING TO"
  56 ISO/ANSI C, UNIX98
  57 .SH "SEE ALSO"
  58 .BR wcsrtombs (3)
  59 .SH NOTES
  60 The behaviour of \fBwcstombs\fP() depends on the LC_CTYPE category of the
  61 current locale.
  62 .PP
  63 The function \fBwcsrtombs\fP() provides a thread safe interface to the same
  64 functionality.