SML datatypes in 32 bit linux and 64 bit linux

Question

I presume that in Standard ML :

• int is 32 bit on 32bit linux

On 64 bit linux is int also 32 bit? Furthermore is there a place (url) where the size of different datatypes is outlined, for Standard ML? Thanks

Answer 1

The size of integers is implementation-specific - it's not specified by the standard. In MoscowML uses 31-bit integers on 32-bit platforms and 63-bit integers on 64-bit platforms according to its documentation.

SML/NJ apparently uses 31-bit integers on both 64-bit and 32-bit systems (I say apparently because I didn't find this documented anywhere - I just tested it on my 64-bit machine).

In MLton the size of Int can even be set using the -default-type command line argument to the compiler.