man3/wcstok.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
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   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 WCSTOK 3  1999-07-25 "GNU" "Linux Programmer's Manual"
  15 .SH NAME
  16 wcstok \- split wide-character string into tokens
  17 .SH SYNOPSIS
  18 .nf
  19 .B #include <wchar.h>
  20 .sp
  21 .BI "wchar_t *wcstok(wchar_t *" wcs ", const wchar_t *" delim ", wchar_t **" ptr );
  22 .fi
  23 .SH DESCRIPTION
  24 The
  25 .BR wcstok ()
  26 function is the wide-character equivalent of the
  27 .BR strtok (3)
  28 function,
  29 with an added argument to make it multithread-safe.
  30 It can be used
  31 to split a wide-character string \fIwcs\fP into tokens, where a token is
  32 defined as a substring not containing any wide-characters from \fIdelim\fP.
  33 .PP
  34 The search starts at \fIwcs\fP, if \fIwcs\fP is not NULL,
  35 or at \fI*ptr\fP, if \fIwcs\fP is NULL.
  36 First, any delimiter wide-characters are skipped, i.e. the
  37 pointer is advanced beyond any wide-characters which occur in \fIdelim\fP.
  38 If the end of the wide-character string is now
  39 reached,
  40 .BR wcstok ()
  41 returns NULL, to indicate that no tokens
  42 were found, and stores an appropriate value in \fI*ptr\fP,
  43 so that subsequent calls to
  44 .BR wcstok ()
  45 will continue to return NULL.
  46 Otherwise, the
  47 .BR wcstok ()
  48 function recognizes the beginning of a token
  49 and returns a pointer to it, but before doing that, it zero-terminates the
  50 token by replacing the next wide-character which occurs in \fIdelim\fP with
  51 a L'\\0' character, and it updates \fI*ptr\fP so that subsequent calls will
  52 continue searching after the end of recognized token.
  53 .SH "RETURN VALUE"
  54 The
  55 .BR wcstok ()
  56 function returns a pointer to the next token,
  57 or NULL if no further token was found.
  58 .SH "CONFORMING TO"
  59 C99.
  60 .SH NOTES
  61 The original \fIwcs\fP wide-character string is destructively modified during
  62 the operation.
  63 .SH EXAMPLE
  64 The following code loops over the tokens contained in a wide-character string.
  65 .sp
  66 .nf
  67 wchar_t *wcs = ...;
  68 wchar_t *token;
  69 wchar_t *state;
  70 for (token = wcstok(wcs, " \\t\\n", &state);
  71     token != NULL;
  72     token = wcstok(NULL, " \\t\\n", &state)) {
  73     ...
  74 }
  75 .fi
  76 .SH "SEE ALSO"
  77 .BR strtok (3),
  78 .BR wcschr (3)