Use pthread mutex instead of semaphore

(the latter need -lpthread on modern Linux anyway)

Makefile

@@ -14,6 +14,9 @@ include config.mk
 # The version of the shared .so libraries
 SO_VERSION := 1
 
+# Link with math libs (NAN) and pthread (mutex)
+LDFLAGS += -lm -lpthread
+
 # Check if there is a doxygen we can run
 ifndef DOXYGEN
   DOXYGEN := $(shell which doxygen)
@@ -90,6 +93,7 @@ SOURCES = $(SRC)/xchange.c $(SRC)/xstruct.c $(SRC)/xlookup.c $(SRC)/xjson.c
 # Generate a list of object (obj/*.o) files from the input sources
 OBJECTS := $(subst .c,.o,$(subst $(SRC),$(OBJ),$(SOURCES)))
 
+
 $(LIB)/libxchange.so: $(LIB)/libxchange.so.$(SO_VERSION)
 
 # Shared library

README.md

@@ -82,7 +82,7 @@ prior to invoking `make`. The following build variables can be configured:
 
  - `WEXTRA`: If set to 1, `-Wextra` is added to `CFLAGS` automatically.
 
- - `LDFLAGS`: Extra linker flags (default: _not set_). Note, `-lm` will be added automatically.
+ - `LDFLAGS`: Extra linker flags (default: _not set_). Note, `-lm -lpthread` will be added automatically.
 
  - `CHECKEXTRA`: Extra options to pass to `cppcheck` for the `make check` target
 

config.mk

@@ -53,9 +53,6 @@ CHECKOPTS ?= --enable=performance,warning,portability,style --language=c \
 # Below are some generated constants based on the one that were set above
 # ============================================================================
 
-# Link against math libs (for e.g. isnan())
-LDFLAGS += -lm
-
 # Search for files in the designated locations
 vpath %.h $(INC)
 vpath %.c $(SRC)

src/xlookup.c

@@ -11,7 +11,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
-#include <semaphore.h>
+#include <pthread.h>
 
 #define __XCHANGE_INTERNAL_API__      ///< Use internal definitions
 #include "xchange.h"
@@ -29,7 +29,7 @@ typedef struct {
   XLookupEntry **table;
   int nBins;
   int nEntries;
-  sem_t sem;
+  pthread_mutex_t mutex;
 } XLookupPrivate;
 
 /// \endcond
@@ -148,10 +148,10 @@ int xLookupPut(XLookupTable *tab, const char *prefix, const XField *field, XFiel
   p = (XLookupPrivate *) tab->priv;
   if(!p) return x_error(0, EINVAL, "xGetLookupEntryAsync", "lookup table not initialized");
 
-  if(sem_wait(&p->sem) != 0) return x_error(X_FAILURE, errno, fn, "sem_wait() error");
+  if(pthread_mutex_lock(&p->mutex) != 0) return x_error(X_FAILURE, errno, fn, "sem_wait() error");
 
   res = xLookupPutAsync(tab, prefix, field, oldValue);
-  sem_post(&p->sem);
+  pthread_mutex_unlock(&p->mutex);
 
   return res;
 }
@@ -183,13 +183,13 @@ XField *xLookupRemove(XLookupTable *tab, const char *id) {
     return NULL;
   }
 
-  if(sem_wait(&p->sem) != 0) {
+  if(pthread_mutex_lock(&p->mutex) != 0) {
     x_error(0, errno, fn, "sem_wait() error");
     return NULL;
   }
 
   f = xLookupRemoveAsync(tab, id);
-  sem_post(&p->sem);
+  pthread_mutex_unlock(&p->mutex);
 
   return f;
 }
@@ -295,10 +295,10 @@ int xLookupPutAll(XLookupTable *tab, const char *prefix, const XStructure *s, bo
   p = (XLookupPrivate *) tab->priv;
   if(!p) return x_error(0, EINVAL, "xGetLookupEntryAsync", "lookup table not initialized");
 
-  if(sem_wait(&p->sem) != 0) return x_error(X_FAILURE, errno, fn, "sem_wait() error");
+  if(pthread_mutex_lock(&p->mutex) != 0) return x_error(X_FAILURE, errno, fn, "sem_wait() error");
 
   n = xLookupPutAllAsync(tab, prefix, s, recursive);
-  sem_post(&p->sem);
+  pthread_mutex_unlock(&p->mutex);
 
   prop_error(fn, n);
   return n;
@@ -330,10 +330,10 @@ int xLookupRemoveAll(XLookupTable *tab, const char *prefix, const XStructure *s,
   p = (XLookupPrivate *) tab->priv;
   if(!p) return x_error(0, EINVAL, "xGetLookupEntryAsync", "lookup table not initialized");
 
-  if(sem_wait(&p->sem) != 0) return x_error(X_FAILURE, errno, fn, "sem_wait() error");
+  if(pthread_mutex_lock(&p->mutex) != 0) return x_error(X_FAILURE, errno, fn, "sem_wait() error");
 
   n = xLookupRemoveAllAsync(tab, prefix, s, recursive);
-  sem_post(&p->sem);
+  pthread_mutex_unlock(&p->mutex);
 
   prop_error(fn, n);
   return n;
@@ -371,7 +371,7 @@ XLookupTable *xAllocLookup(unsigned int size) {
   x_check_alloc(p->table);
 
   p->nBins = n;
-  sem_init(&p->sem, FALSE, 1);
+  pthread_mutex_init(&p->mutex, NULL);
 
   tab = (XLookupTable *) calloc(1, sizeof(XLookupTable));
   x_check_alloc(tab);
@@ -453,13 +453,13 @@ XField *xLookupField(const XLookupTable *tab, const char *id) {
     return NULL;
   }
 
-  if(sem_wait(&p->sem) != 0) {
+  if(pthread_mutex_lock(&p->mutex) != 0) {
     x_error(0, errno, fn, "sem_wait() error");
     return NULL;
   }
 
   e = xGetLookupEntryAsync(tab, id, xGetHash(id));
-  sem_post(&p->sem);
+  pthread_mutex_unlock(&p->mutex);
 
   return e ? e->field : NULL;
 }
@@ -495,7 +495,7 @@ void xDestroyLookup(XLookupTable *tab) {
     }
 
     free(p->table);
-    sem_destroy(&p->sem);
+    pthread_mutex_destroy(&p->mutex);
   }
 
   free(tab);

test/Makefile

@@ -2,6 +2,8 @@
 INC = ../include
 BUILD_MODE = debug
 
+LDFLAGS += -lm
+
 # Load the common Makefile definitions...
 include ../config.mk