STRTOK(3)                 OpenBSD Programmer's Manual                STRTOK(3)

NAME
     strtok, strtok_r - string token operations

SYNOPSIS
     #include <string.h>

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

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

DESCRIPTION
     This interface is obsoleted by strsep(3).

     The strtok() function is used to isolate sequential tokens in a null-ter-
     minated 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 fur-
     ther tokens from the same string, should pass a null pointer instead.
     The separator string, sep, must be supplied each time, and may change be-
     tween calls.

     The strtok_r() function is a version of strtok() that takes an explicit
     context argument and is reentrant.

     The strtok() and strtok_r() functions return a pointer to the beginning
     of each subsequent token in the string, after replacing the separator
     character itself with an ASCII NUL character.  When no more tokens re-
     main, a null pointer is returned.

     Since strtok() and strtok_r() modify the string, str should not point to
     an area in the initialized data segment.

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))) {
                   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
     memchr(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 C'').

BUGS
     The System V strtok(), if handed a string containing only delimiter char-
     acters, 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.

OpenBSD 3.5                      June 29, 1991                               2