2.11BSD/src/man/man3/strsep.3

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.\"	@(#)strsep.3	8.1.1 (2.11BSD) 1996/1/12
.\"
.TH STRSEP 3 "January 12, 1996"
.UC 7
.SH NAME
\fBstrsep\fP \- separate strings
.SH SYNOPSIS
.B #include <string.h>
.sp
.B char *
.br
\fBstrsep\fP(stringp, delim)
.br
.I char **stringp;
.br
.I char *delim;
.SH DESCRIPTION
The
.BR strsep ()
function locates, in the string referenced by
.I *stringp ,
the first occurrence of any character in the string
.I delim
(or the terminating
`\e0'
character) and replaces it with a
`\e0'.
The location of the next character after the delimiter character
(or NULL, if the end of the string was reached) is stored in
.I *stringp .
The original value of
.I *stringp
is returned.
.PP
An ``empty'' field, i.e. one caused by two adjacent delimiter characters,
can be detected by comparing the location referenced by the pointer returned
in
.I *stringp
to
`\e0'.
.PP
If
.I *stringp
is initially
.BR NULL ,
.BR strsep ()
returns
.BR NULL .
.SH EXAMPLES
The following uses
.BR strsep ()
to parse a string, containing tokens delimited by white space, into an
argument vector:
.sp
.nf
.cs R 24
char **ap, *argv[10], *inputstring;

for (ap = argv; (*ap = strsep(&inputstring, " \et")) != NULL;)
	if (**ap != '\e0')
		++ap;
.br
.cs R
.fi
.SH HISTORY
The
.BR strsep ()
function
is intended as a replacement for the
.BR strtok ()
function.
While the
.BR strtok ()
function should be preferred for portability reasons (it conforms to
ANSI C X3.159-1989 (``ANSI C''))
it is unable to handle empty fields, i.e. detect fields delimited by
two adjacent delimiter characters, or to be used for more than a single
string at a time.
The
.BR strsep ()
function first appeared in 4.4BSD.