# HG changeset patch
# User Sebastien Jodogne <s.jodogne@gmail.com>
# Date 1515054436 -3600
# Node ID 2a211c0fc7cae9675ce0282589279236c22e7b56
# Parent  cbb8deaacdf7aed7d4db067ab256546e9a74192b
note about ar

diff -r cbb8deaacdf7 -r 2a211c0fc7ca Resources/CMake/Compiler.cmake
--- a/Resources/CMake/Compiler.cmake	Wed Jan 03 20:25:35 2018 +0100
+++ b/Resources/CMake/Compiler.cmake	Thu Jan 04 09:27:16 2018 +0100
@@ -200,7 +200,12 @@
   # exist a duplicate object name (e.g. a/Foo.cpp.o, b/Foo.cpp.o), the
   # resulting static library can end up having only one of the
   # duplicate objects. [...] This bug only happens if there are many
-  # objects." https://cmake.org/Bug/view.php?id=14874
+  # objects." The trick consists in replacing the "r" argument
+  # ("replace") provided to "ar" (as used in CMake < 3.1) by the "q"
+  # argument ("quick append"). This is because of the fact that CMake
+  # will invoke "ar" several times with several batches of ".o"
+  # objects, and using "r" would overwrite symbols defined in
+  # preceding batches. https://cmake.org/Bug/view.php?id=14874
   set(CMAKE_CXX_ARCHIVE_APPEND "<CMAKE_AR> <LINK_FLAGS> q <TARGET> <OBJECTS>")
 endif()