diff --git a/src/common/mac/macho_reader.cc b/src/common/mac/macho_reader.cc
index 6d7207ce..52f3c411 100644
--- a/src/common/mac/macho_reader.cc
+++ b/src/common/mac/macho_reader.cc
@@ -181,15 +181,15 @@ void Reader::Reporter::LoadCommandRegionTruncated() {
 
 void Reader::Reporter::LoadCommandsOverrun(size_t claimed, size_t i,
                                            LoadCommandType type) {
-  fprintf(stderr, "%s: file's header claims there are %ld"
-          " load commands, but load command #%ld",
+  fprintf(stderr, "%s: file's header claims there are %zu"
+          " load commands, but load command #%zu",
           filename_.c_str(), claimed, i);
   if (type) fprintf(stderr, ", of type %d,", type);
   fprintf(stderr, " extends beyond the end of the load command region\n");
 }
 
 void Reader::Reporter::LoadCommandTooShort(size_t i, LoadCommandType type) {
-  fprintf(stderr, "%s: the contents of load command #%ld, of type %d,"
+  fprintf(stderr, "%s: the contents of load command #%zu, of type %d,"
           " extend beyond the size given in the load command's header\n",
           filename_.c_str(), i, type);
 }