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@(#)strtok.3 5.4 (Berkeley) 05/17/90

C 3 strtok, strsep - string token operations

#include <string.h>

char *
strtok(char *str, const char *sep);

This interface is obsoleted by strsep(3).

Strtok is used to isolate sequential tokens in a null-terminated string, str . These tokens are separated in the string by "one or more" 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.

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.

index(3), memchr(3), rindex(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strsep(3), strspn(3), strstr(3) Strtok conforms to ANSI X3.159-1989 (``ANSI C''). There is no way to get tokens from multiple strings simultaneously.

The System V strtok will, if handed a string containing only delimiter characters, 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.