add an initial implementation.

src/Makefile.am

@@ -36,14 +36,15 @@ endif
 include_HEADERS = space.h runner.h queue.h task.h lock.h cell.h part.h const.h \
     engine.h swift.h serial_io.h timers.h debug.h scheduler.h proxy.h parallel_io.h \
     common_io.h single_io.h multipole.h map.h tools.h partition.h clocks.h parser.h \
-    physical_constants.h physical_constants_cgs.h potentials.h version.h hydro_properties.h
+    physical_constants.h physical_constants_cgs.h potentials.h version.h \
+    hydro_properties.h threadpool.h
 
 # Common source files
 AM_SOURCES = space.c runner.c queue.c task.c cell.c engine.c \
     serial_io.c timers.c debug.c scheduler.c proxy.c parallel_io.c \
     units.c common_io.c single_io.c multipole.c version.c map.c \
     kernel_hydro.c kernel_gravity.c tools.c part.c partition.c clocks.c parser.c \
-    physical_constants.c potentials.c hydro_properties.c
+    physical_constants.c potentials.c hydro_properties.c threadpool.c
 
 # Include files for distribution, not installation.
 nobase_noinst_HEADERS = approx_math.h atomic.h cycle.h error.h inline.h kernel_hydro.h kernel_gravity.h \

src/threadpool.h

@@ -25,6 +25,9 @@
 /* Some standard headers. */
 #include <pthread.h>
 
+/* Function type for mappings. */
+typedef void (*threadpool_map_function)(void *map_data, void *extra_data);
+
 /* Data of a threadpool. */
 struct threadpool {
 
@@ -35,17 +38,21 @@ struct threadpool {
   pthread_t *threads;
 
   /* This is where threads go to rest. */
-  pthread_mutex_t sleep_mutex;
-  pthread_cond_t sleep_cond;
-  
+  pthread_mutex_t control_mutex, thread_mutex;
+  pthread_cond_t control_cond, thread_cond;
+
   /* Current map data and count. */
   void *map_data;
   size_t map_data_count, map_data_size, map_data_stride;
+  threadpool_map_function map_function;
+  
+  /* Counter for the number of threads that are done. */
+  int num_threads_done;
 };
 
 /* Function prototypes. */
 void threadpool_init(struct threadpool *tp, int num_threads);
-void threadpool_map(struct threadpool *tp, void *map_data, size_t N, int stride,
-                    void *extra_data);
+void threadpool_map(struct threadpool *tp, threadpool_map_function map_function,
+                    void *map_data, size_t N, int stride, void *extra_data);
 
 #endif /* SWIFT_THREADPOOL_H */