strtok - extract token from string
char *strtok(char *s, const char *delim));
A `token' is a nonempty string of characters not occurring
in the string delim, followed by \0 or by a character occur-
ring in delim.
The strtok() function can be used to parse the string s into
tokens. The first call to strtok() should have s as its
first argument. Subsequent calls should have the first argu-
ment set to NULL. Each call returns a pointer to the next
token, or NULL when no more tokens are found.
If a token ends with a delimiter, this delimiting character
is overwritten with a \0 and a pointer to the next character
is saved for the next call to strtok. The delimiter string
delim may be different for each call.
Never use this function. This function modifies its first
argument. The identity of the delimiting character is lost.
This function cannot be used on constant strings.
The strtok() function returns a pointer to the next token,
or NULL if there are no more tokens.
SVID 3, POSIX, BSD 4.3, ISO 9899
index(3), memchr(3), rindex(3), strpbrk(3), strsep(3),