False Positive uninitdata with compound assignment operators

[Aaron Danen]

Hello

malloc() initializes buf, but not buf[0]. The following is valid because buf is never dereferenced

void f() {
    char *buf = (char *)malloc(1);
    if (!buf)
        return NULL;
    buf += 1;
    free(buf - 1);
}

however, cppcheck throws

examples/buf.c:5:5: error: Memory is allocated but not initialized: buf [uninitdata]
    buf += 1;
    ^

For this similar code, cppcheck correctly throws no errors

void f() {
    char *buf = (char *)malloc(1);
    if (!buf)
        return NULL;
    buf = buf + 1;
    free(buf - 1);
}

I think this is because checkuninitvar is has explicit handling for "=". I have a patch to modify checkuninitvar.cpp to handle the other assignment operators like "+=" and "-=". If it is useful I can submit at PR. Thanks!

-- Aaron

[CHR]

Thanks for reporting, ticket is here: https://trac.cppcheck.net/ticket/15005