xref: /netbsd/lib/libc/string/strsep.3 (revision c4a72b64)
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35.\"     from: @(#)strsep.3	8.1 (Berkeley) 6/9/93
36.\"	$NetBSD: strsep.3,v 1.12 2002/08/20 16:22:44 wiz Exp $
37.\"
38.Dd August 11, 2002
39.Dt STRSEP 3
40.Os
41.Sh NAME
42.Nm strsep
43.Nd separate strings
44.Sh LIBRARY
45.Lb libc
46.Sh SYNOPSIS
47.Fd #include \*[Lt]string.h\*[Gt]
48.Ft char *
49.Fn strsep "char **stringp" "const char *delim"
50.Sh DESCRIPTION
51The
52.Fn strsep
53function locates, in the null-terminated string referenced by
54.Fa *stringp ,
55the first occurrence of any character in the string
56.Fa delim
57(or the terminating
58.Ql \e0
59character) and replaces it with a
60.Ql \e0 .
61The location of the next character after the delimiter character
62(or NULL, if the end of the string was reached) is stored in
63.Fa *stringp .
64The original value of
65.Fa *stringp
66is returned.
67.Pp
68An
69.Dq empty
70field, i.e. one caused by two adjacent delimiter characters,
71can be detected by comparing the location referenced by the pointer returned
72by
73.Fn strsep
74to
75.Ql \e0 .
76.Pp
77If
78.Fa *stringp
79is initially
80.Dv NULL ,
81.Fn strsep
82returns
83.Dv NULL .
84.Sh EXAMPLES
85The following uses
86.Fn strsep
87to parse a string, containing tokens delimited by white space, into an
88argument vector:
89.Bd -literal -offset indent
90char **ap, *argv[10], *inputstring;
91
92for (ap = argv; ap < \*[Am]argv[9] \*[Am]\*[Am]
93    (*ap = strsep(\*[Am]inputstring, " \et")) != NULL;) {
94	if (**ap != '\e0')
95		ap++;
96}
97.Ed
98.Sh HISTORY
99The
100.Fn strsep
101function
102is intended as a replacement for the
103.Fn strtok
104function.
105While the
106.Fn strtok
107function should be preferred for portability reasons (it conforms to
108.St -ansiC )
109it is unable to handle empty fields, i.e. detect fields delimited by
110two adjacent delimiter characters, or to be used for more than a single
111string at a time.
112The
113.Fn strsep
114function first appeared in
115.Bx 4.4 .
116