diff --git a/file_writer.cc b/file_writer.cc
index 07bdb46..1a95a75 100644
--- a/file_writer.cc
+++ b/file_writer.cc
@@ -15,7 +15,7 @@
   return 0;
 }
 
-int DirectFileWriter::Write(const void* bytes, size_t count) {
+ssize_t DirectFileWriter::Write(const void* bytes, size_t count) {
   CHECK_GE(fd_, 0);
   const char* char_bytes = reinterpret_cast<const char*>(bytes);