1 files changed, 22 insertions, 4 deletions

diff --git a/src/knowledge/knowledge.c b/src/knowledge/knowledge.c
index 463d40b..c9bfc2a 100644
--- a/src/knowledge/knowledge.c
+++ b/src/knowledge/knowledge.c
@@ -1,5 +1,6 @@
 #include <stdlib.h>
 #include <string.h>
+#include <stdio.h>
 #include <stdint.h> /* defines SIZE_MAX */
 
 #include "../pipe/pipe.h"
@@ -9,8 +10,10 @@
 /** Basic functions of the ZoO_knowledge structure ****************************/
 
 /* See: "knowledge.h" */
-void ZoO_knowledge_initialize (struct ZoO_knowledge k [const static 1])
+int ZoO_knowledge_initialize (struct ZoO_knowledge k [const restrict static 1])
 {
+   int error;
+
    k->words = (struct ZoO_knowledge_word *) NULL;
    k->words_length = 0;
    k->words_sorted = (ZoO_index *) NULL;
@@ -18,6 +21,22 @@ void ZoO_knowledge_initialize (struct ZoO_knowledge k [const static 1])
    k->sequences = (ZoO_index **) NULL;
    k->sequences_length = 0;
    k->sequences_sorted = (ZoO_index *) NULL;
+
+   error = pthread_mutex_init(&(k->mutex), (const pthread_mutexattr_t *) NULL);
+
+   if (error != 0)
+   {
+      fprintf
+      (
+         stderr,
+         "[F] Unable to initialize knowledge mutex: %s.\n",
+         strerror(error)
+      );
+
+      return -1;
+   }
+
+   return 0;
 }
 
 int ZoO_knowledge_lock_access
@@ -26,8 +45,7 @@ int ZoO_knowledge_lock_access
    const struct ZoO_pipe io [const restrict static 1]
 )
 {
-   /* TODO */
-   return 0;
+   return pthread_mutex_lock(&(k->mutex));
 }
 
 void ZoO_knowledge_unlock_access
@@ -36,5 +54,5 @@ void ZoO_knowledge_unlock_access
    const struct ZoO_pipe io [const restrict static 1]
 )
 {
-   /* TODO */
+   pthread_mutex_unlock(&(k->mutex));
 }