Cast ssize_t or size_t
c++, casting, size-t
Solution
There is no one right answer to this question. There are several possible answers, depending on what you know a priori about the values that those variables may take on.
If you know that `sst` is non-negative, then you can safely cast `sst` to `size_t`, as this will not change the value (incidentally, this is what happens if you have no cast at all).
If `sst` might be negative but you know that `st` will never be larger than `SSIZE_MAX`, then you can safely cast `st` to `ssize_t`, as this will not change the value.
If `sst` might be negative, and `st` might be larger than `SSIZE_MAX`, then neither cast is correct; either one could change the value, resulting in an incorrect comparison. Instead, you would do the following `if (sst >= 0 && (size_t)sst == st)`.
If you’re not absolutely certain that one of the first two situations applies, choose the third option as it is correct in all cases.
Problem
In source files which I am using in my project, there is a comparison between `ssize_t` and `size_t` variables: ``` ssize_t sst; size_t st; if(sst == st){...} ``` I would like to get rid of the warning: ``` warning: comparison between signed and unsigned integer expressions ``` But I am not sure, which variable should I cast to the other? ``` if((size_t)sst == st){...} ``` or ``` if(sst == (ssize_t)st){...} ``` What is safer, better, cleaner? Thanks