porting linux 32 bit app to 64 bit?

Question

i'm about to port very large scale application to 64 Bits, i've noticed in that in the web there some articles which shows many pitfalls of this porting , i wondered if there is any tool which can assist in porting to 64 bit , meaning finding the places in code that needs to be changed.... maybe the gcc with warnnings enabled... is it good enough ? is there anything better ?

EDIT: Guys i am searching for a tool if any that might be a complete to the compiler, i know GCC can asist , but i doubt it will find all un portable problems that
will be discovered in run-time....maybe static code analysis tool that emphasize porting to 64 bits ?

thanks

Answer 1

Here's a guide. Another one

Size of some data types are different in 32-bit and 64-bit OS, so check for place where the code is assuming the size of data types. eg If you were casting a pointer to an int, that won't work in 64bit. This should fix most of the issues.

If your app uses third-party libraries, make sure those work in 64-bit too.

Answer 2

A good tool is called grep ;-) do

grep -nH -e '\<int\>\|\<short\>\|\<long\>' *

and replace all bare uses of these basic integer types by the proper one:

• array indices should be size_t
• pointer casts should be uintptr_t
• pointer differences should be prtdiff_t
• types with an assumption of width N should be uintN_t

and so on, I probably forgot some. Then gcc with all warnings on will tell you. You could also use clang as a compiler it gives even more diagnostics.