Do I need -64 ???
When you compile with -n32, the chip executes in 64-bit mode and the software restricts addresses to 32 bits
Compile with -n32 when you want:
- To generate smaller executables than for -64
- Executables to have fewer data cache misses and less memory paging than for -64
Compile with -64 if your program:
- Requires more than 2 gigabytes of address space
- Will overflow a 32-bit long integer (for C)
C Type -n32 -64 Fortran Type
------ ------- ------ --------------
short int 16 16 integer*2
long long int 64 64 integer*8
long double 64 128 real*16