usr/src/lib/libc/string/strtok.3

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.\"     @(#)strtok.3    5.5 (Berkeley) 6/23/90
.\"
.TH STRTOK 3 "June 23, 1990"
.UC 3
.SH NAME
strtok, strsep \- string token operations
.SH SYNOPSIS
.nf
.ft B
#include <string.h>

char *
strtok(char *str, const char *sep);
.ft R
.fi
.SH DESCRIPTION
.ft B
This interface is obsoleted by strsep(3).
.ft R
.PP
.I Strtok
is used to isolate sequential tokens in a null-terminated string,
.IR str .
These tokens are separated in the string by
.B "one or more"
of the characters in
.IR sep .
The first time that
.I strtok
is called,
.I str
should be specified; subsequent calls, wishing to obtain further tokens
from the same string, should pass a null pointer instead.
The separator string,
.IR sep ,
must be supplied each time, and may change between calls.
.PP
.I Strtok
returns a pointer to the start of each subsequent token in the string,
after replacing the token itself with a NUL character.
When no more tokens remain, a null pointer is returned.
.SH SEE ALSO
index(3), memchr(3), rindex(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3),
strsep(3), strspn(3), strstr(3)
.SH STANDARDS
.B Strtok
conforms to ANSI X3.159-1989 (``ANSI C'').
.SH BUGS
There is no way to get tokens from multiple strings simultaneously.
.PP
The System V
.B strtok
will, if handed a string containing only delimiter characters,
not alter the next starting point, so that a call to
.B strtok
with a different (or empty) delimiter string
may return a non-NULL value.
Since this implementation always alters the next starting point,
such a sequence of calls would always return NULL.