diff --git a/src/zmalloc.c b/src/zmalloc.c
index 094dd80fa..01ac8c797 100644
--- a/src/zmalloc.c
+++ b/src/zmalloc.c
@@ -147,6 +147,10 @@ void *zrealloc(void *ptr, size_t size) {
     size_t oldsize;
     void *newptr;
 
+    if (size == 0 && ptr!=NULL) {
+        zfree(ptr);
+        return NULL;
+    }
     if (ptr == NULL) return zmalloc(size);
 #ifdef HAVE_MALLOC_SIZE
     oldsize = zmalloc_size(ptr);