类型为pthread_mutex_t的不明确引用

Question

I have declared

pthread_mutex_t mutex=PTHREAD_MUTEX_INITIALIZER;

in the global space of my main program, main.cpp.

However, whenever I try to refer to it in a function definition, for example,

void foo(void)
{
    pthread_mutex_lock(&mutex);
    ...
}

the following error message will be displayed:

reference to 'mutex' is ambiguous

Any idea what's going on? If it helps, this is being written in xcode, and I have included in the header of the program.

Answer 1

It turns out after I changed to name from mutex to mutex1, the errors disappeared. I guess because mutex is a function somewhere...