STRTOK(3)						   BSD Library Functions Manual 						 STRTOK(3)

NAME

     strtok, strtok_r -- string tokens

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <string.h>

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

     char *
     strtok_r(char *str, const char *sep, char **lasts);

DESCRIPTION

     The strtok() function is used to isolate sequential tokens in a nul-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 separator character
     itself with a NUL character.  Separator characters at the beginning of the string or at the continuation point are skipped so that zero
     length tokens are not returned.  When no more tokens remain, a null pointer is returned.

     The strtok_r() function implements the functionality of strtok() but is passed an additional argument, lasts, which points to a user-provided
     pointer which is used by strtok_r() to store state which needs to be kept between calls to scan the same string; unlike strtok(), it is not
     necessary to limit tokenizing to a single string at a time when using strtok_r().

EXAMPLES

     The following will construct an array of pointers to each individual word in the string s:

	   #define MAXTOKENS	   128

	   char s[512], *p, *tokens[MAXTOKENS];
	   char *last;
	   int i = 0;

	   snprintf(s, sizeof(s), "cat dog horse cow");

	   for ((p = strtok_r(s, " ", &last)); p;
	       (p = strtok_r(NULL, " ", &last)), i++) {
		   if (i < MAXTOKENS - 1)
			   tokens[i] = p;
	   }
	   tokens[i] = NULL;

     That is, tokens[0] will point to "cat", tokens[1] will point to "dog", tokens[2] will point to "horse", and tokens[3] will point to "cow".

SEE ALSO

     index(3), memchr(3), rindex(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strsep(3), strspn(3), strstr(3)

STANDARDS

     The strtok() function conforms to ANSI X3.159-1989 (``ANSI C89'').  The strtok_r() function conforms to IEEE Std 1003.1c-1995 (``POSIX.1'').

BUGS

     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.

BSD
								  August 11, 2002							       BSD