diff --git a/src/impl/getusername.cpp b/src/impl/getusername.cpp
index 203ed5e7e..d369a4a3d 100644
--- a/src/impl/getusername.cpp
+++ b/src/impl/getusername.cpp
@@ -43,8 +43,8 @@ BOOL GetUserName(WCHAR_T *lpBuffer, LPDWORD lpnSize)
 	}
 
 	// Get username from system in a thread-safe manner
-	char userName[L_cuserid];
-	int err = getlogin_r(userName, L_cuserid);
+	char userName[LOGIN_NAME_MAX];
+	int err = getlogin_r(userName, LOGIN_NAME_MAX);
 	// Map errno to Win32 Error Codes
 	if (err != 0) {
 		switch (errno) {
diff --git a/src/tests/test-getusername.cpp b/src/tests/test-getusername.cpp
index b58387b26..8e025a2de 100644
--- a/src/tests/test-getusername.cpp
+++ b/src/tests/test-getusername.cpp
@@ -114,8 +114,8 @@ TEST_F(GetUserNameTest, BufferSizeAsUserNamePlusOne) {
 	TestSuccess();
 }
 
-TEST_F(GetUserNameTest, L_cuseridSize) {
-	// L_cuserid is big enough to hold any username
-	TestWithSize(L_cuserid);
+TEST_F(GetUserNameTest, BufferSizeAsLoginNameMax) {
+	// LoginNameMax is big enough to hold any username
+	TestWithSize(LOGIN_NAME_MAX);
 	TestSuccess();
 }