Simple C (C99) re-entrant "foreach" loop macro to split a string into tokens separated by delimiter and loop over them

foreach_token.h

#include <string.h>

/* (c) 2015 Wojciech Owczarek - BSD Clause 2 licence - I'm too lazy to paste it */

#ifndef __FOREACH_TOKEN_H
#define __FOREACH_TOKEN_H

/* handy default delimiter - space, comma, semicolon or tab */
#define DEFAULT_TOKEN_DELIM ", ;\t"

/*
 * foreach loop across substrings from @var, delimited by @delim, placing
 * each token in @targetvar on iteration, using @id variable name prefix
 * to allow nesting (each loop uses an individual set of variables).
 * @id is only a string identifier, so the end macro can identify which
 * helper pointer to free. We need to duplicate the string, because strtok
 * functions alter it. We also need to free the duplicate. A counter variable
 * (counter_@id) is defined and incremented from zero, so we know which token we
 * are processing. The counter is incremented once again when ending the loop,
 * so in the end contains the total number of tokens found.
 *
 * Note: because this is a macro, if you forget the end call, you're missing
 * a closing bracket and compiler errors will not clearly show what happened.
 */

#define foreach_token_begin(id, var, targetvar, delim) \
    int counter_##id = -1;     /* iteration counter - start from -1 because we increment at the top of the loop */ \
    char* stash_##id = NULL;   /* temporary pointer for strtok_r() - in strtok() this is static */ \
    char* text_##id;           /* copy of our string */ \
    char* text__##id;          /* pointer to our copy, which has to be used once only */ \
    char* targetvar;           /* our target variable for the token */ \
    text_##id=strdup(var); \
    for(text__##id = text_##id;;text__##id = NULL) { /* why nullify? because strtoks require this */ \
        targetvar = strtok_r(text__##id, delim, &stash_##id); \
        if(targetvar == NULL) break; /* no (more) tokens */ \
        counter_##id++;

#define foreach_token_end(id) } \
    if(text_##id != NULL) { \
        free(text_##id); /* thou shall free what thou strdupeth */ \
    } \
    counter_##id++; /* because the for loop does no incrementing here */

 /* example usage (semicolons are not necessary when invoking begin_ and end_) */
 
 /*
 
 foreach_token_begin(names, "Bob, Jake Steve; Norman   Lucy", name, DEFAULT_TOKEN_DELIM);
 
  foreach_token_begin(animals, "frog:cougar:fruit bat:tarsier", animal, ":");
 
   printf("%s\'s animal number %d is a %s.\n", name, counter_animals + 1, animal);
 
  foreach_token_end(animals);
  
  printf("this was a list of %s\'s %d animals.\n", name, counter_animals);
 
 foreach_token_end(names);
 
 printf("a total of %d people have animals\n.", counter_names);
 
 */

#endif /* __FOREACH_TOKEN_H */