Sample Program

The following sample program, foo.c, directly illustrates the effect of the LP64 versus ILP32 data models. The same program can be compiled as either a 32-bit program or a 64-bit program.

#include <stdio.h>
int
main(int argc, char *argv[])
{
		(void) printf("char is \t\t%lu bytes\n", sizeof (char));
		(void) printf("short is \t%lu bytes\n", sizeof (short));
		(void) printf("int is \t\t%lu bytes\n", sizeof (int));
		(void) printf("long is \t\t%lu bytes\n", sizeof (long));
		(void) printf("long long is \t\t%lu bytes\n", sizeof (long long));
		(void) printf("pointer is \t%lu bytes\n", sizeof (void *));
		return (0);
} 

The result of 32-bit compilation is:

% cc -O -o foo32 foo.c
% foo32 
char is          1 bytes
short is         2 bytes
int is           4 bytes
long is          4 bytes
long long is     8 bytes
pointer is       4 bytes   

The result of 64-bit compilation is:

% cc -xarch=v9 -O -o foo64 foo.c 
% foo64
char is          1 bytes
short is         2 bytes
int is           4 bytes
long is          8 bytes
long long is     8 bytes 
pointer is       8 bytes

The default compilation environment is designed to maximize portability, that is, to create 32-bit applications.