xref: /netbsd-src/lib/libc/string/strsep.3 (revision d20841bb642898112fe68f0ad3f7b26dddf56f07)
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31.\"     from: @(#)strsep.3	8.1 (Berkeley) 6/9/93
32.\"	$NetBSD: strsep.3,v 1.14 2003/08/07 16:43:52 agc Exp $
33.\"
34.Dd August 11, 2002
35.Dt STRSEP 3
36.Os
37.Sh NAME
38.Nm strsep
39.Nd separate strings
40.Sh LIBRARY
41.Lb libc
42.Sh SYNOPSIS
43.In string.h
44.Ft char *
45.Fn strsep "char **stringp" "const char *delim"
46.Sh DESCRIPTION
47The
48.Fn strsep
49function locates, in the null-terminated string referenced by
50.Fa *stringp ,
51the first occurrence of any character in the string
52.Fa delim
53(or the terminating
54.Ql \e0
55character) and replaces it with a
56.Ql \e0 .
57The location of the next character after the delimiter character
58(or NULL, if the end of the string was reached) is stored in
59.Fa *stringp .
60The original value of
61.Fa *stringp
62is returned.
63.Pp
64An
65.Dq empty
66field, i.e. one caused by two adjacent delimiter characters,
67can be detected by comparing the location referenced by the pointer returned
68by
69.Fn strsep
70to
71.Ql \e0 .
72.Pp
73If
74.Fa *stringp
75is initially
76.Dv NULL ,
77.Fn strsep
78returns
79.Dv NULL .
80.Sh EXAMPLES
81The following uses
82.Fn strsep
83to parse a string, containing tokens delimited by white space, into an
84argument vector:
85.Bd -literal -offset indent
86char **ap, *argv[10], *inputstring;
87
88for (ap = argv; ap < \*[Am]argv[9] \*[Am]\*[Am]
89    (*ap = strsep(\*[Am]inputstring, " \et")) != NULL;) {
90	if (**ap != '\e0')
91		ap++;
92}
93.Ed
94.Sh HISTORY
95The
96.Fn strsep
97function
98is intended as a replacement for the
99.Fn strtok
100function.
101While the
102.Fn strtok
103function should be preferred for portability reasons (it conforms to
104.St -ansiC )
105it is unable to handle empty fields, i.e. detect fields delimited by
106two adjacent delimiter characters, or to be used for more than a single
107string at a time.
108The
109.Fn strsep
110function first appeared in
111.Bx 4.4 .
112