diff --git a/main.cpp b/main.cpp
index 183ec102..c90e892a 100644
--- a/main.cpp
+++ b/main.cpp
@@ -2232,7 +2232,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 
 	estimated_complexity = geompos;
 	fflush(geomfile);
-	if (pwrite(fileno(geomfile), &estimated_complexity, sizeof(estimated_complexity), 0) != 0) {
+	if (pwrite(fileno(geomfile), &estimated_complexity, sizeof(estimated_complexity), 0) != sizeof(estimated_complexity)) {
 		perror("pwrite estimated complexity");
 		exit(EXIT_WRITE);
 	}
diff --git a/tile.cpp b/tile.cpp
index 7e9eb5d0..9c0c9e58 100644
--- a/tile.cpp
+++ b/tile.cpp
@@ -2094,7 +2094,7 @@ long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, ch
 
 				if (additional[A_TRUNCATE_ZOOMS]) {
 					fflush(geomfile[j]->fp);
-					if (pwrite(fileno(geomfile[j]->fp), &estimated_complexity_out, sizeof(estimated_complexity_out), start_geompos[j]) != 0) {
+					if (pwrite(fileno(geomfile[j]->fp), &estimated_complexity_out, sizeof(estimated_complexity_out), start_geompos[j]) != sizeof(estimated_complexity_out)) {
 						perror("pwrite complexity");
 						exit(EXIT_WRITE);
 					}