gzip: Add pure attribute

1 files changed, 1 insertions, 1 deletions

diff --git a/src/gzip.h b/src/gzip.h
index 7283e3f..28aa9d5 100644
--- a/src/gzip.h
+++ b/src/gzip.h
@@ -66,7 +66,7 @@ int
 opkg_opk_gzip_write(struct opkg_opk_gzip *gzip, void *record, size_t size);
 
 size_t
-opkg_opk_gzip_written(struct opkg_opk_gzip *gzip);
+opkg_opk_gzip_written(struct opkg_opk_gzip *gzip) __attribute__((__pure__));
 
 int
 opkg_opk_gzip_finish_write(struct opkg_opk_gzip *gzip);