diff --git a/core/os_linux.odin b/core/os_linux.odin
index 90250a625..99eea1a47 100644
--- a/core/os_linux.odin
+++ b/core/os_linux.odin
@@ -179,11 +179,11 @@ seek :: proc(fd: Handle, offset: i64, whence: int) -> (i64, Errno) {
 	return res, 0;
 }
 
-file_size :: proc(fd: Handle) -> (i64, bool) {
+file_size :: proc(fd: Handle) -> (i64, Errno) {
 	prev, _ := seek(fd, 0, SEEK_CUR);
 	size, err := seek(fd, 0, SEEK_END);
 	seek(fd, prev, SEEK_SET);
-	return size, err != 0;
+	return size, err;
 }
 
 
diff --git a/core/os_x.odin b/core/os_x.odin
index ecbed3f27..fcc39c218 100644
--- a/core/os_x.odin
+++ b/core/os_x.odin
@@ -196,11 +196,11 @@ seek :: proc(fd: Handle, offset: AddressSize, whence: int) -> (AddressSize, Errn
 	return final_offset, 0;
 }
 
-file_size :: proc(fd: Handle) -> (i64, bool) {
+file_size :: proc(fd: Handle) -> (i64, Errno) {
 	prev, _ := seek(fd, 0, SEEK_CUR);
 	size, err := seek(fd, 0, SEEK_END);
 	seek(fd, prev, SEEK_SET);
-	return size, err != 0;
+	return size, err;
 }