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In C I have a pointer that is declared volatile and initialized null.
void* volatile pvoid;
Thread 1 is occasionally reading the pointer value to check if it is non-null. Thread 1 will not set the value of the pointer.
Thread 2 will set the value of a pointer just once.
I believe I can get away without using a mutex or condition variable.
Is there any reason thread 1 will read a corrupted value or thread 2 will write a corrupted value?
In the case where the value fits in a single register, such as a memory aligned pointer, this is safe. In other cases where it might take more than one instruction to read or write the value, the read thread could get corrupted data. If you are not sure wether the read and write will take a single instruction in all usage scenarios, use atomic reads and writes.