I want to write a .h file conforming to C89 that would be understood by most C preprocessors like gcc, cl (Visual Studio) etc. and that would determine the data model used, i.e. how many bits the (unsigned) short, (unsigned) int and (unsigned) long types occupy. Where can I find the necessary macros? For instance, are there macros I can evaluate in order to find out whether the data model is e.g. ILP32, LP64, LLP64 or something else? It is fine for me to use compiler-specific macros, but I do not want to use architecture-specific or OS-specific macros. If possible, please also provide the necessary macros to check which compiler is used. Thank you!
ADDED 2: The goal is to allow for type definitions depending on the data model. For instance, if long is at least 48-bit wide, a 48-bit key type could be defined as long, but if not, I would need a struct for that. On the other hand, I do not want to rely on anything not guaranteed by C89, like "long is either 32-bit or 64-bit, so if ULONG_MAX != 0xFFFFFFFFlu, then long is wider than 48-bit", which does not have to be true on all C89-conforming compilers.
ADDED 1:Here, the predefined GCC macros are described. Hence I can do the following:
#if defined(__GNUC__)#define SHRT_BIT __SHRT_WIDTH__#define INT_BIT __INT_WIDTH__#define LONG_BIT __LONG_WIDTH__#elif ???# ???#endifprintf("short is %u-bit\n""int is %u-bit\n""long is %u-bit\n", SHRT_BIT, INT_BIT, LONG_BIT);Are there similar macros for other widely used compilers like cl (Visual Studio), which I could add at the location of the ??? in the code?