Kernel+LibPthread: Implement pthread_join()

It's now possible to block until another thread in the same process has
exited. We can also retrieve its exit value, which is whatever value it
passed to pthread_exit(). :^)

1 files changed, 7 insertions, 1 deletions

diff --git a/Libraries/LibPthread/pthread.cpp b/Libraries/LibPthread/pthread.cpp
index 26761b8a02..b659d376d1 100644
--- a/Libraries/LibPthread/pthread.cpp
+++ b/Libraries/LibPthread/pthread.cpp
@@ -1,10 +1,11 @@
 #include <AK/StdLibExtras.h>
+#include <Kernel/Syscall.h>
 #include <pthread.h>
 #include <unistd.h>
 
 extern "C" {
 
-int pthread_create(pthread_t* thread, pthread_attr_t* attributes, void *(*start_routine)(void*), void* argument_to_start_routine)
+int pthread_create(pthread_t* thread, pthread_attr_t* attributes, void* (*start_routine)(void*), void* argument_to_start_routine)
 {
     if (!thread)
         return -EINVAL;
@@ -21,4 +22,9 @@ void pthread_exit(void* value_ptr)
     exit_thread(value_ptr);
 }
 
+int pthread_join(pthread_t thread, void** exit_value_ptr)
+{
+    int rc = syscall(SC_join_thread, thread, exit_value_ptr);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
 }