Compiler Warnings – Understanding and Resolving Them

Your question doesn't seem to actually be about how we report compiler errors - rather, it's about the classification of problems and what to do about them.

If we start by assuming, for the moment, that the warning/error dichotomy is correct, let's see how well we can build on top of that. Some ideas:

1. Different "levels" of warning. A lot of compilers sort-of implement this (for example GCC has lots of switches for configuring exactly what it will warn about), but it needs work - for example, reporting what severity a reported warning is, and the ability to set "warnings are errors" for only warnings above a specified severity.

2. Sane classification of errors and warnings. An error should only be reported if the code doesn't meet the specification, and hence cannot be compiled. Unreachable statements, while probably a coding error, should be a warning, not an error - the code is still "valid", and there are legitimate instances in which one would want to compile with unreachable code (quick modifications for debugging, for instance).

Now things I disagree with you on:

1. Making extra effort to report every problem. If there's an error, that breaks the build. The build is broken. The build will not work until that error is fixed. Hence, it's better to report that error immediately, rather than "carrying on" in order to try and identify everything else "wrong" with the code. Especially when a lot of those things are probably caused by the initial error anyway.

2. Your specific example of a warning-that-should-be-an-error. Yes, it's probably a programmer mistake. No, it shouldn't break the build. If I know the input to the function is such that it will always return a value, I should be able to run the build and do some tests without having to add those extra checks. Yes, it should be a warning. And a damn high-severity one at that. But it shouldn't break the build in and of itself, unless compiling with warnings-are-errors.

Thoughts?

So the size of cl.exe is 158 KB. What do you think?

The rest of the MSVC C++ compiler is in various DLLs. The C/C++ compiler driver is officially cl.exe, but many of the driver functions are provided by MsBuild. Other executables include link.exe, lib.exe, ml.exe and bscmake.exe. You can't translate the archictecture or terminology blindly from one product set to another that is completely different.

However, if all you want to do is compile from the command line, cl.exe is the place to go. Details can be found here: https://stackoverflow.com/questions/7865432/command-line-compile-using-cl-exe.