man3/strsep.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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  25 .\" References consulted:
  26 .\"     Linux libc source code
  27 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  28 .\"     386BSD man pages
  29 .\" Modified Sat Jul 24 18:00:10 1993 by Rik Faith (faith@cs.unc.edu)
  30 .\" Modified Mon Jan 20 12:04:18 1997 by Andries Brouwer (aeb@cwi.nl)
  31 .\" Modified Tue Jan 23 20:23:07 2001 by Andries Brouwer (aeb@cwi.nl)
  32 .\"
  33 .TH STRSEP 3  2019-03-06 "GNU" "Linux Programmer's Manual"
  34 .SH NAME
  35 strsep \- extract token from string
  36 .SH SYNOPSIS
  37 .nf
  38 .B #include <string.h>
  39 .PP
  40 .BI "char *strsep(char **" stringp ", const char *" delim );
  41 .fi
  42 .PP
  43 .in -4n
  44 Feature Test Macro Requirements for glibc (see
  45 .BR feature_test_macros (7)):
  46 .in
  47 .PP
  48 .BR strsep ():
  49     Since glibc 2.19:
  50         _DEFAULT_SOURCE
  51     Glibc 2.19 and earlier:
  52         _BSD_SOURCE
  53 .SH DESCRIPTION
  54 If
  55 .I *stringp
  56 is NULL, the
  57 .BR strsep ()
  58 function returns NULL
  59 and does nothing else.
  60 Otherwise, this function finds the first token
  61 in the string
  62 .IR *stringp ,
  63 that is delimited by one of the bytes in the string
  64 .IR delim .
  65 This token is terminated by overwriting the delimiter
  66 with a null byte (\(aq\e0\(aq),
  67 and
  68 .I *stringp
  69 is updated to point past the token.
  70 In case no delimiter was found, the token is taken to be
  71 the entire string
  72 .IR *stringp ,
  73 and
  74 .I *stringp
  75 is made NULL.
  76 .SH RETURN VALUE
  77 The
  78 .BR strsep ()
  79 function returns a pointer to the token,
  80 that is, it returns the original value of
  81 .IR *stringp .
  82 .SH ATTRIBUTES
  83 For an explanation of the terms used in this section, see
  84 .BR attributes (7).
  85 .TS
  86 allbox;
  87 lb lb lb
  88 l l l.
  89 Interface       Attribute       Value
  90 T{
  91 .BR strsep ()
  92 T}      Thread safety   MT-Safe
  93 .TE
  94 .SH CONFORMING TO
  95 4.4BSD.
  96 .SH NOTES
  97 The
  98 .BR strsep ()
  99 function was introduced as a replacement for
 100 .BR strtok (3),
 101 since the latter cannot handle empty fields.
 102 However,
 103 .BR strtok (3)
 104 conforms to C89/C99 and hence is more portable.
 105 .SH BUGS
 106 Be cautious when using this function.
 107 If you do use it, note that:
 108 .IP * 2
 109 This function modifies its first argument.
 110 .IP *
 111 This function cannot be used on constant strings.
 112 .IP *
 113 The identity of the delimiting character is lost.
 114 .SH SEE ALSO
 115 .BR index (3),
 116 .BR memchr (3),
 117 .BR rindex (3),
 118 .BR strchr (3),
 119 .BR string (3),
 120 .BR strpbrk (3),
 121 .BR strspn (3),
 122 .BR strstr (3),
 123 .BR strtok (3)