C/stdlib.h/strtoul
strtoul: converts the string into an unsigned long int according to the base of the number
//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));
}
/*0*/