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STRTOK(3)             DragonFly 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 * restrict str, const char * restrict sep,
         char ** restrict last);


DESCRIPTION

     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 implementation will behave as if no library function calls strtok().

     The strtok_r() function is a reentrant version of strtok().  The context
     pointer last must be provided on each call.  The strtok_r() function may
     also be used to nest two parsing loops within one another, as long as
     separate context pointers are used.

     The strtok() and strtok_r() functions return 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.


EXAMPLES

     The following uses strtok_r() to parse two strings using separate
     contexts:

     char test[80], blah[80];
     char *sep = "\\/:;=-";
     char *word, *phrase, *brkt, *brkb;

     strcpy(test, "This;is.a:test:of=the/string\\tokenizer-function.");

     for (word = strtok_r(test, sep, &brkt);
          word;
          word = strtok_r(NULL, sep, &brkt))
     {
         strcpy(blah, "blah:blat:blab:blag");

         for (phrase = strtok_r(blah, sep, &brkb);
              phrase;
              phrase = strtok_r(NULL, sep, &brkb))
         {
             printf("So far we're at %s:%s\n", word, phrase);
         }
     }


SEE ALSO

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


STANDARDS

     The strtok() function conforms to ISO/IEC 9899:1990 (``ISO C90'').


AUTHORS

     Wes Peters, Softweyr LLC <wes@softweyr.com>

     Based on the FreeBSD 3.0 implementation.


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.

DragonFly 5.1                  February 22, 2018                 DragonFly 5.1

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