OpenMP strange behaviour

Question

Hello I have the following code, which I compile with gcc (>4.2) with -fopenmp flag:

int main(void)
{
#pragma omp parallel for
    int i; 
    for(i=0;i<4;i++) while(1);

    return 0;
}

I get a SIGSEGV on OSX Lion (ver 1.7.3, llvm-gcc 4.2.1) and CentOS 6.2 . What am I doing wrong here? Thanks

Answer 1

Not sure if this is relevant to the compiler version and configuration but while(true){} terminates

More precisely, if you write a loop which

• makes no calls to library I/O functions, and
• does not access or modify volatile objects, and
• performs no synchronization operations (1.10) or atomic operations (Clause 29)

and does not terminate, you have undefined behaviour.

This may end up not applying to your situation, but as C++11 becomes more established, watch out.