xref: /freebsd/lib/libc/string/strsep.3 (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
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31.\"	@(#)strsep.3	8.1 (Berkeley) 6/9/93
32.\" $FreeBSD$
33.\"
34.Dd June 9, 1993
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 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., a character in the string
67.Fa delim
68occurs as the first character of
69.Fa *stringp )
70can be detected by comparing the location referenced by the returned pointer
71to
72.Ql \e0 .
73.Pp
74If
75.Fa *stringp
76is initially
77.Dv NULL ,
78.Fn strsep
79returns
80.Dv NULL .
81.Sh EXAMPLES
82The following uses
83.Fn strsep
84to parse a string, containing tokens delimited by white space, into an
85argument vector:
86.Bd -literal -offset indent
87char **ap, *argv[10], *inputstring;
88
89for (ap = argv; (*ap = strsep(&inputstring, " \et")) != NULL;)
90	if (**ap != '\e0')
91		if (++ap >= &argv[10])
92			break;
93.Ed
94.Sh SEE ALSO
95.Xr memchr 3 ,
96.Xr strchr 3 ,
97.Xr strcspn 3 ,
98.Xr strpbrk 3 ,
99.Xr strrchr 3 ,
100.Xr strspn 3 ,
101.Xr strstr 3 ,
102.Xr strtok 3
103.Sh HISTORY
104The
105.Fn strsep
106function
107is intended as a replacement for the
108.Fn strtok
109function.
110While the
111.Fn strtok
112function should be preferred for portability reasons (it conforms to
113.St -isoC )
114it is unable to handle empty fields, i.e., detect fields delimited by
115two adjacent delimiter characters, or to be used for more than a single
116string at a time.
117The
118.Fn strsep
119function first appeared in
120.Bx 4.4 .
121