From: Andre Noll <maan@tuebingen.mpg.de>
Date: Mon, 24 Aug 2015 15:34:28 +0000 (+0200)
Subject: Explain the osl_strerror dance.
X-Git-Tag: v0.1.3~11
X-Git-Url: http://git.tuebingen.mpg.de/?p=osl.git;a=commitdiff_plain;h=7aa320514ebbb20f6c237627bf0bc8e509321f21;ds=sidebyside

Explain the osl_strerror dance.

It's not completely obvious what is going on here and *why* we not
just go with a simple pointer array for the messages returned by
osl_strerror(). This commit explains why pointer arrays are bad
in DSOs.
---

diff --git a/osl.c b/osl.c
index 6666196..e31811b 100644
--- a/osl.c
+++ b/osl.c
@@ -13,7 +13,14 @@
 #include "util.h"
 #include "osl_core.h"
 
-/* Taken from Drepper: How to write shared libraries, Appendix B. */
+/*
+ * Taken from Drepper: How to write shared libraries, Appendix B.
+ *
+ * The main reason for this rather fancy implementation of strerror() is to
+ * avoid having an array of pointers. This is desirable because initialized
+ * pointer variables increase the startup time of the library due to the
+ * processing of relocations.
+ */
 #include <stddef.h>
 #define MSGSTRFIELD(line) MSGSTRFIELD1(line)
 #define MSGSTRFIELD1(line) str##line