GCC: Break compilation on "control reaches end of non-void function"

Question

When I add

#pragma GCC diagnostic error "-Wreturn-type"

the compiler produces warnings, not errors for each missing return. How can I make it turn this particular warning into an error?

Test code:

#pragma GCC diagnostic error "-Wreturn-type"

int foo(int x)
{
    if (x) return 8;
}

int main(int narg, char* arg[])
{
    foo(narg);
}

I have tried with

i686-apple-darwin10-g++-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5666) (dot 3)

i686-apple-darwin10-llvm-g++-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.6)

UPDATE: I have tried -Werror=return-type as suggested by @sastraxi, but it has the same effect.

Answer 1

Try passing -Werror=return-type to gcc!