strtoul - converts the string into an unsigned long int according to the base of the number in C

//Header:     #include <stdlib.h>  
//Declaration:  unsigned long int strtoul(const char *start, char **end, int radix); 
 

#include <stdlib.h>

int main(void){

    char *start, *end;
    char a[100];

    end = a;
    *start= "12341234";
    printf("%d", strtoul(start, &end, 8));

}