Re: A clean way to account for machine word sizes in XS code?

[tonyc]

in reply to A clean way to account for machine word sizes in XS code?

For the typemap you need to add typemap entries that map your types to the same as the other int types, eg. in typemap:

gf2_u8     T_UV
gf2_u16    T_UV
gf2_u32    T_UV
gf2_s8     T_IV
gf2_s16    T_IV
gf2_s32    T_IV

ExtUtils::MakeMaker should pick up the type map automatically when you run Makefile.PL.

As to whether those types are the correct types, one possibility is stdint.h, which requires a C99 compiler/libc, but in most cases, if the C compiler has 8 and 16 bit int types, char and short will be them.

Unfortunately perl doesn't probe for stdint.h, so it's something you'd need to probe for yourself.

For 32-bit, long might be 64-bit*, so in the absence of inttypes.h you could use limits.h:

#include <limits.h>

#if USHRT_MAX > 0x80000000
typedef unsigned short gf2_u32;
#elif UINT_MAX > 0x80000000
typedef unsigned gf2_u32;
#else
typedef unsigned long gf2_u32;
#endif

* According to the standard, they could all be 128-bit, but most likely char is 8 bit if the compiler has an 8-bit type, and unless the compiler has stdint.h, short will be the 16 bit type if there is one.