How can I split up a string into whitespace-separated fields? How can I duplicate the process by which main() is handed argc and argv?

The only Standard function available for this kind of ``tokenizing'' is strtok, although it can be tricky to use and it may not do everything you want it to. (For instance, it does not handle quoting.) Here is a usage example, which simply prints each field as it's extracted:

#include <stdio.h>

#include <string.h>

char string[] = "this is a test"; /* not char *;

char *p;

for(p = strtok(string, " tn"); p != NULL;

p = strtok(NULL, " tn"))

printf(""%s"n", p);

As an alternative, here is a routine I use for building an argv all at once:

#include <ctype.h>

int makeargv(char *string, char *argv[], int argvsize)

{

char *p = string;

int i;

int argc = 0;

for(i = 0; i < argvsize; i++) {

/* skip leading whitespace */

while(isspace(*p))

p++;

if(*p != '')

argv[argc++] = p;

else {

argv[argc] = 0;

break;

}

/* scan over arg */

while(*p != '' && !isspace(*p))

p++;

/* terminate arg: */

if(*p != '' && i < argvsize-1)

*p++ = '';

}

return argc;

}

Calling makeargv is straightforward:

char *av[10];

int i, ac = makeargv(string, av, 10);

for(i = 0; i < ac; i++)

printf(""%s"n", av[i]);