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cc-preprocessorpreprocessor

Getting variable size in C preprocessor

i have an problem, i am writing a header file, which depending on the Sizes of the c standard datatypes, defines different Structs and Unions. I would need something like this:

#if sizeof(int) == 4
    typedef struct {
        int i;
    } test;
#else
    typedef struct {
        long i;
    } test;
#endif

sadly this doesnt work.

Does somebody know, how i can do this?

Thanks for your help.

Solution

  • You cant do it this way as preprocessor does not know anything about the C language, but for this purpose you have fixed size integer types which are standard and portable

    typedef struct {
    int32_t i;
} test;