2 files changed, 2 insertions, 2 deletions
diff --git a/src/utility/io.cc b/src/utility/io.cc
index 3f54c6f..ae895c4 100644
--- a/src/utility/io.cc
+++ b/src/utility/io.cc
@@ -19,7 +19,7 @@ FileDescriptorGuard::~FileDescriptorGuard() {
 	close(this->fd_);
 }
 
-FileDescriptorGuard::operator int() {
+FileDescriptorGuard::operator int() const {
 	return this->fd_;
 }
 
diff --git a/src/utility/io.h b/src/utility/io.h
index 1015ddb..363c458 100644
--- a/src/utility/io.h
+++ b/src/utility/io.h
@@ -10,7 +10,7 @@ class FileDescriptorGuard {
 		FileDescriptorGuard(const std::string& path);
 		~FileDescriptorGuard();
 
-		operator int();
+		operator int() const;
 
 	private:
 		int fd_;