Different ways of checking the return value of alloc functions affects the results

[Amarghosh]

In the following snippet, cppcheck does not report a memleak if the return value is explicitly compared against a value, as in the case of a2. But at the same time, if we just check if (getaddrinfo()) as in the case of a1, which is a widely used pattern to check if the function returned zero or not, it reports a false positive memleak. Invocation command was cppcheck --library=posix.cfg main.c, and the version was 2.14.2

    struct addrinfo *a1 = NULL;
    if (getaddrinfo("a", "b", NULL, &a1)) {
        return -1; // false positive memleak reported here
    }
    freeaddrinfo(a1);

    struct addrinfo *a2 = NULL;
    if (getaddrinfo("a", "b", NULL, &a2) != 0) {
        return -1; // no false positive memleak here
    }
    freeaddrinfo(a2);

It would be nice if you could treat if (func()) same as if (func() != 0).

[CHR]

Thanks for reporting, fixed by https://github.com/danmar/cppcheck/pull/6671

[Amarghosh]

Thank you! That was really fast :)