Question

The following code does not give a warning with g++ 4.1.1 and -Wall.

int octalStrToInt(const std::string& s)
{    
    return strtol(s.c_str(), 0, 8);
}

I was expecting a warning because strtol returns a long int but my function is only returning a plain int. Might other compilers emit a warning here? Should I cast the return value to int in this case as a good practice?

Answer 1

You may need the -Wconversion flag to turn these warnings on. However, it won’t warn about long -> int, since they are the same size with GCC (the value won’t change because of the conversion). But it would if you convert for example long -> short

I suppose simply doing a cast would not be recommended, since that would just cover up the possibility of bugs. It would be OK after you have checked that such a cast won’t modify the value to appease the compiler.