In this example in the malloc() what does the UL do?
#include <stdio.h> /* perror */
#include <errno.h> /* errno */
#include <stdlib.h> /* malloc, free, exit */
int main(void)
{
/* Pointer to char, requesting dynamic allocation of 2,000,000,000
* storage elements (declared as an integer constant of type
* unsigned long int). (If your system has less than 2 GB of memory
* available, then this call to malloc will fail.)
*/
char *ptr = malloc(2000000000UL);
if (ptr == NULL) {
perror("malloc failed");
/* here you might want to exit the program or compensate
for that you don't have 2GB available
*/
} else {
/* The rest of the code hereafter can assume that 2,000,000,000
* chars were successfully allocated...
*/
free(ptr);
}
exit(EXIT_SUCCESS); /* exiting program */
}
