char *trim(char *str)
{
    size_t len = 0;
    char *frontp = str;
    char *endp = NULL;

    if( str == NULL ) { return NULL; }
    if( str[0] == '\0' ) { return str; }

    len = strlen(str);
    endp = str + len;

    /* Move the front and back pointers to address the first non-whitespace
     * characters from each end.
     */
    while( isspace((unsigned char) *frontp) ) { ++frontp; }
    if( endp != frontp )
    {
        while( isspace((unsigned char) *(--endp)) && endp != frontp ) {}
    }

    if( str + len - 1 != endp )
            *(endp + 1) = '\0';
    else if( frontp != str &&  endp == frontp )
            *str = '\0';

    /* Shift the string so that it starts at str so that if it's dynamically
     * allocated, we can still free it on the returned pointer.  Note the reuse
     * of endp to mean the front of the string buffer now.
     */
    endp = str;
    if( frontp != str )
    {
            while( *frontp ) { *endp++ = *frontp++; }
            *endp = '\0';
    }


    return str;
}

test@ws1:/tmp$ cat strtok.c
#include <stdio.h>
#include <string.h>
int main(int argc, char *argv[])
{
        static char string[] = { "\t\t    option1=100,option2=200    " };

        char *s = string;
        char *token = NULL;

        while (( token  = strtok(s, " \t,") )) {
                printf("\"%s\"\n", token);
                s = NULL ;  /* strtok() only wants the pointer on the first invocation */
        }

        return 0;
}
test@ws1:/tmp$ cc -Wall -o strtok strtok.c 
test@ws1:/tmp$ ./strtok 
"option1=100"
"option2=200"
test@ws1:/tmp$