double pointer vs pointer to array, incompatible pointer type

Question

Having this:

#define _DEFAULT_SOURCE 1
#include 
#include 

int main(){
    char *token, org[] = "Cats,Dogs,Mice,,,Dwarves         


        

Answer 1

The strsep function requires the address of a modifiable pointer as its first argument (or NULL, in which case it does nothing); you are passing it the (fixed) address of an array. You can fix this by declaring a separate char* variable and assigning to that the (address of the) org array:

int main()
{
    char* token, org[] = "Cats,Dogs,Mice,,,Dwarves,Elves:High,Elves:Wood";
    char* porg = org; // "porg" is a MODIFIABLE pointer initialized with the start address of the "org" array
    while ((token = strsep(&porg, ",")))
        printf("Token: %s\n", token);

    return 0;
}

From the Linux manual page (bolding mine):

If *stringp is NULL, the strsep() function returns NULL and does nothing else. Otherwise, this function finds the first token in the string *stringp, that is delimited by one of the bytes in the string delim. This token is terminated by overwriting the delimiter with a null byte ('\0'), and *stringp is updated to point past the token. In case no delimiter was found, the token is taken to be the entire string *stringp, and *stringp is made NULL.

On the meaning and use of the restrict keyword, maybe this will help: Realistic usage of the C99 'restrict' keyword?.