Why does mktime never return -1?

Question

C++ / C#

I convert the struct tm structure to time_t with the mktime function , which should return -1 if the values ​​are incorrect. But in my case, this does not happen, that is, even if I specify tm_mday = 32, then mktime will not return -1, but will return the number of seconds, but already from the first day of the next month, if we translate seconds into human form.

Answer 1

Incorrect = does not fit into time_t. Everything else is correct, mktime will correct values ​​that go beyond normal limits. Read the manuals carefully.