Compile program for both 32 and 64 bit?

[raigs]

N00B. If I compile a simple Hello World! program on a 64bit linux, will it work on a 32bit linux? (I'm using gcc).

#include <stdio.h>

int main(void)
{
	printf("Hello World!");
	return 0;
}

[Ancient Dragon]

>> If I compile a simple Hello World! program on a 64bit linux, will it work on a 32bit linux?

Depends on the flags you give the compiler. The default is to produce 32-bit code, but you can tell it to produce 64-bit code. Just because you are running a 64-bit operating system doesn't mean the compiler will automatically produce 64-bit code.

[gerard4143]

If you installed a 64 bit version of Linux on a 64 bit box, then the default compiler(gcc) will produce 64 bit code...that is unless you set the appro. switches telling it to produce 32 bit code...

[ankur_]

If you want to run the program with the 32 bit compiler include -m32 in your compiler option

[raigs]

If you want to run the program with the 32 bit compiler include -m32 in your compiler option

1. Can I compile a single program than runs on both 32 and 64?

2. I have a 64bit Debian Linux and tried to compile using -m32 but returned error. I'm probably missing some package. Any ideas?

raigs@mycomputer:~/Desktop$ gcc -m32 pig.c
In file included from /usr/include/features.h:361,
                 from /usr/include/stdio.h:28,
                 from pig.c:1:
/usr/include/gnu/stubs.h:7:27: error: gnu/stubs-32.h: No such file or directory
raigs@mycomputer:~/Desktop$

[ankur_]

1. Can I compile a single program than runs on both 32 and 64?

2. I have a 64bit Debian Linux and tried to compile using -m32 but returned error. I'm probably missing some package. Any ideas?

raigs@mycomputer:~/Desktop$ gcc -m32 pig.c
In file included from /usr/include/features.h:361,
                 from /usr/include/stdio.h:28,
                 from pig.c:1:
/usr/include/gnu/stubs.h:7:27: error: gnu/stubs-32.h: No such file or directory
raigs@mycomputer:~/Desktop$

There are diffrent compiler options for 32 bit and 64 bit in diffrent platforms.
You can get more detail about that in the below link.
http://www.openlinksw.com/dataspace/dav/wiki/Main/VOSMake