man3/strsep.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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  23 .\" References consulted:
  24 .\"     Linux libc source code
  25 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  26 .\"     386BSD man pages
  27 .\" Modified Sat Jul 24 18:00:10 1993 by Rik Faith (faith@cs.unc.edu)
  28 .\" Modified Mon Jan 20 12:04:18 1997 by Andries Brouwer (aeb@cwi.nl)
  29 .\" Modified Tue Jan 23 20:23:07 2001 by Andries Brouwer (aeb@cwi.nl)
  30 .\"
  31 .TH STRSEP 3  2011-09-28 "GNU" "Linux Programmer's Manual"
  32 .SH NAME
  33 strsep \- extract token from string
  34 .SH SYNOPSIS
  35 .nf
  36 .B #include <string.h>
  37 .sp
  38 .BI "char *strsep(char **" stringp ", const char *" delim );
  39 .fi
  40 .sp
  41 .in -4n
  42 Feature Test Macro Requirements for glibc (see
  43 .BR feature_test_macros (7)):
  44 .in
  45 .sp
  46 .BR strsep ():
  47 _BSD_SOURCE
  48 .SH DESCRIPTION
  49 If \fI*stringp\fP is NULL, the
  50 .BR strsep ()
  51 function returns NULL
  52 and does nothing else.
  53 Otherwise, this function finds the first token
  54 in the string \fI*stringp\fP, where tokens
  55 are delimited by symbols in the string \fIdelim\fP.
  56 This token is terminated by overwriting the delimiter
  57 with a null byte (\(aq\\0\(aq)
  58 and \fI*stringp\fP is updated to point past the token.
  59 In case no delimiter was found, the token is taken to be
  60 the entire string \fI*stringp\fP, and \fI*stringp\fP is made NULL.
  61 .SH RETURN VALUE
  62 The
  63 .BR strsep ()
  64 function returns a pointer to the token,
  65 that is, it returns the original value of \fI*stringp\fP.
  66 .SH CONFORMING TO
  67 4.4BSD.
  68 .SH NOTES
  69 The
  70 .BR strsep ()
  71 function was introduced as a replacement for
  72 .BR strtok (3),
  73 since the latter cannot handle empty fields.
  74 However,
  75 .BR strtok (3)
  76 conforms to C89/C99 and hence is more portable.
  77 .SH BUGS
  78 Be cautious when using this function.
  79 If you do use it, note that:
  80 .IP * 2
  81 This function modifies its first argument.
  82 .IP *
  83 This function cannot be used on constant strings.
  84 .IP *
  85 The identity of the delimiting character is lost.
  86 .SH SEE ALSO
  87 .BR index (3),
  88 .BR memchr (3),
  89 .BR rindex (3),
  90 .BR strchr (3),
  91 .BR string (3),
  92 .BR strpbrk (3),
  93 .BR strspn (3),
  94 .BR strstr (3),
  95 .BR strtok (3)