diff --git a/glib/docs.c b/glib/docs.c
index 19aad0e96..5031a6225 100644
--- a/glib/docs.c
+++ b/glib/docs.c
@@ -617,7 +617,9 @@
  * goffset:
  *
  * A signed integer type that is used for file offsets,
- * corresponding to the C99 type off64_t.
+ * corresponding to the POSIX type `off_t` as if compiling with
+ * `_FILE_OFFSET_BITS` set to 64. #goffset is always 64 bits wide, even on
+ * 32-bit architectures.
  * Values of this type can range from #G_MINOFFSET to
  * #G_MAXOFFSET.
  *