issue #82: added doc about DCAS support

[libcds.git] / cds / details / defs.h

diff --git a/cds/details/defs.h b/cds/details/defs.h
index 594c8229c4b504961006775b0eeb52fa4a7f16da..6c737efa2d3dcaf766c00548ec8fe6d2eab308b0 100644 (file)
--- a/cds/details/defs.h
+++ b/cds/details/defs.h
@@ -169,6 +169,14 @@
    - \p boost.thread (thread-loal storage support), boost.system
    - \p google-test
 
+   Some parts of libcds may depend on DCAS (double-width compare-and-swap) atomic primitive if
+   the target architecture supports it. For x86, cmake build script enables -mcx16 compiler flag that
+   switches DCAS support on. You may manually disable DCAS support with the following  command line flags
+   in GCC/clang (for MS VC++ compiler DCAS is not supported):
+   - \p -DCDS_DISABLE_128BIT_ATOMIC - for 64bit build
+   - \p -DCDS_DISABLE_64BIT_ATOMIC - for 32bit build
+   @warning All your projects AND libcds MUST be compiled with the same flags - either with DCAS support or without it.
+
    \par Windows build
 
    Prerequisites: for building <b>cds</b> library and test suite you need: