Table 2: Useful options in GCC to catch 64-bit porting problems.

Option Description
-Wpadded Warns that padding was added to the structure.
-Wformat Check calls to printf and scanf have correct format strings.
-Wsign-compare Warn when a comparison between signed and unsigned values could produce an incorrect result when the signed value is converted to unsigned.
-Wsign-compare Warn when a comparison between signed and unsigned values could produce an incorrect result when the signed value is converted to unsigned.
-Wconversion Warn if a prototype causes a type conversion that is different from what would happen to the same argument in the absence of a prototype.
-Wpointer-arith Warn about anything that depends on the function pointer or of void *.