Pointers versus Integer Sizes

Pointers versus Integer Sizes

You didn't hear this from me, but apparently you can store pointers in integers, and vice-versa, in C++ code. Weirdly, you can even get paid for doing this. But it only works if the byte sizes are big enough, and it's best to self-test this portability risk during program startup. What exactly you want to test depends on what you're (not) doing, but here's one example:

    // Test LONGs can be stored in pointers
    yassert(sizeof(char*) >= sizeof(long));
    yassert(sizeof(void*) >= sizeof(long));
    yassert(sizeof(int*) >= sizeof(long));
    // ... and more

Note that a better version in modern C++ would use “static_assert” to test these sizes at compile-time, with zero runtime cost.

    static_assert(sizeof(char*) >= sizeof(long));
    static_assert(sizeof(void*) >= sizeof(long));
    static_assert(sizeof(int*) >= sizeof(long));

In this way, you can perfectly safely mix pointers and integers in a single variable. Just don't tell the SOC compliance officer.

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