strtok - string tokens
This interface is obsoleted by strsep(3).
The strtok() function is used to isolate sequential tokens in a null-terminated string,
str . These tokens are separated in the string by at least one of the characters in sep .
The first time that strtok() is called, str should be specified; subsequent calls, wishing
to obtain further tokens from the same string, should pass a null pointer instead. The
separator string, sep , must be supplied each time, and may change between calls.
The strtok() function returns a pointer to the beginning 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.
index(3), memchr(3), rindex(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strsep(3),
The strtok() function conforms to ANSI C X3.159-1989 (``ANSI C'').
There is no way to get tokens from multiple strings simultaneously.
The System V strtok(), if handed a string containing only delimiter characters, will not
alter the next starting point, so that a call to 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.
4.4 Berkeley Distribution January 12, 1996 STRTOK(3)