Compile:

#include <pthread.h>
// #include <iostream>
int main() {
   pthread_mutexattr_t *attr;
   pthread_mutexattr_init(attr);
   return 0;
}

You get a link error.

Compile:

#include <pthread.h>
#include <iostream>
int main() {
   pthread_mutexattr_t *attr;
   pthread_mutexattr_init(attr);
   return 0;
}

It compiles with no warnings (g++ -Wall testcase.cpp), but when executed, segfaults. Compiling with -lpthread fixes it, of course, but should this be a link-time error rather than a runtime error?

This bug was originally reported in Ubuntu's Malone bugtracker:

https://launchpad.net/distros/ubuntu/+source/gcc-4.0/+bug/26663