Converion of 64 bit source code to 32 bit source code

[surya1006]

Hi all,
i am having source code which i can easily compile and make a 64 bit application running on a 64 bit system with Fedora 3 - 64 bit as OS , Pentium 4 as processor and a external 64 bit PCI card inserted on the motherboard.
Now i want to run the application on 32 bit system using Fedora-32 bit and 32 bit PCI card the processor will remain same.Can any one please guide me what changes i will have to do to make a 32 bit application.

[meton_magis]

unless your source code depends on the specific memory size of variables, most code can be recompiled on a 32 bit computer and work just fine.

but it depends on what language you're using, and some other stuff maybe.

Fedora 3 is about 5 years old though, and is unsupported.

[surya1006]

Thanks for the reply

I am using C language does the size of variable will be changed like if am using any variable unsigned long int xyz(64 bit) in 64 bit system i have to use long int(32 bit) in 32 bit system ?

[meton_magis]

a lot depends on what compiler you are using. I don't know specificaly how much each uses.

C variable types and declarations - Wikipedia, the free encyclopedia

if you're wanting to program safely, never use a type that you expect to fit MORE than the minimum in the C standard deffinitions.



just out of curiousity, if you KNOW the application compiles and runs on a 64 bit OS, why are you chainging to 32 bit? there is almost no advantage to doing so now, unlike the past when there could be.

[surya1006]

U r right shifting from 64 bit to 32 bit is not a great idea but the problem is that it is a part of a project(we will need approx 100-200 motherboards) now a days it is quite hard to get a 64 bit motherboard with 64 bit PCI-X slot and if u find any it will cost u much that's why i m bound to shift to 32 bit system which i readily available in market and at very cheap price.

[Rubberman]

You should only need to deal with 64-bit variables such as long integers (use long long integers on 32-bit machines) and pointers (if you are converting to integer values and vice-versa). Otherwise, there should not be much you need to do. The integer variable issue is often masked by headers that typedef size-specific types for this purpose, such as:

#ifdef BITS64
typedef unsigned long int uint64;
typedef long int int64;
#else
typedef unsigned long long int uint64;
typedef long long int int64;
#endif /* BITS64 */