diff --git a/tests/binaries/heap-multiple-heaps.c b/tests/binaries/heap-multiple-heaps.c
index 3a9d1dd25..cdeec68ae 100644
--- a/tests/binaries/heap-multiple-heaps.c
+++ b/tests/binaries/heap-multiple-heaps.c
@@ -21,7 +21,7 @@
 /* The expected distance is the chunk size plus room for the metadata. */
 #define EXPECTED_CHUNK_DISTANCE     LESS_THAN_MMAP_THRESHOLD + 24
 
-void *thread()
+void *thread(void *arg)
 {
         void *pointers[NUM_ALLOCS];
         for (int i = 0; i < NUM_ALLOCS; i++) {
diff --git a/tests/binaries/heap-non-main.c b/tests/binaries/heap-non-main.c
index 3a2369f4b..28d4959f2 100644
--- a/tests/binaries/heap-non-main.c
+++ b/tests/binaries/heap-non-main.c
@@ -8,7 +8,7 @@
 #include <pthread.h>
 #include "utils.h"
 
-void *thread()
+void *thread(void *arg)
 {
         void* p1 = malloc(0x18);
         void* p2 = malloc(0x18);