Index: lib/libc/tests/sys/sendfile_test.c
===================================================================
--- lib/libc/tests/sys/sendfile_test.c
+++ lib/libc/tests/sys/sendfile_test.c
@@ -290,8 +290,8 @@
 
 	ATF_REQUIRE_EQ_MSG(dest_file_size, length,
 	    "number of bytes written out to %s (%ju) doesn't match the "
-	    "expected number of bytes (%ju)", dest_filename, dest_file_size,
-	    length);
+	    "expected number of bytes (%ju)", dest_filename,
+	    (uintmax_t)dest_file_size, (uintmax_t)length);
 
 	ATF_REQUIRE_EQ_MSG(0, lseek(src_fd, offset, SEEK_SET),
 	    "lseek failed: %s", strerror(errno));