xref: /freebsd/lib/libc/string/strsep.3 (revision daf1cffce2e07931f27c6c6998652e90df6ba87e)
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35.\"	@(#)strsep.3	8.1 (Berkeley) 6/9/93
36.\" $FreeBSD$
37.\"
38.Dd June 9, 1993
39.Dt STRSEP 3
40.Os
41.Sh NAME
42.Nm strsep
43.Nd separate strings
44.Sh SYNOPSIS
45.Fd #include <string.h>
46.Ft char *
47.Fn strsep "char **stringp" "const char *delim"
48.Sh DESCRIPTION
49The
50.Fn strsep
51function locates, in the string referenced by
52.Fa *stringp ,
53the first occurrence of any character in the string
54.Fa delim
55(or the terminating
56.Ql \e0
57character) and replaces it with a
58.Ql \e0 .
59The location of the next character after the delimiter character
60(or NULL, if the end of the string was reached) is stored in
61.Fa *stringp .
62The original value of
63.Fa *stringp
64is returned.
65.Pp
66An ``empty'' field, i.e. one caused by two adjacent delimiter characters,
67can be detected by comparing the location referenced by the pointer returned
68in
69.Fa *stringp
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 = strsep(&inputstring, " \et")) != NULL;)
89	if (**ap != '\e0')
90		if (++ap >= &argv[10])
91			break;
92.Ed
93.Sh HISTORY
94The
95.Fn strsep
96function
97is intended as a replacement for the
98.Fn strtok
99function.
100While the
101.Fn strtok
102function should be preferred for portability reasons (it conforms to
103.St -ansiC )
104it is unable to handle empty fields, i.e. detect fields delimited by
105two adjacent delimiter characters, or to be used for more than a single
106string at a time.
107The
108.Fn strsep
109function first appeared in
110.Bx 4.4 .
111