Le 13/08/2016 à 16:45, Enrico Forestieri a écrit :
commit 7113fb669dcd193295308c44ee2213aa437e38b2 Author: Enrico Forestieri <for...@lyx.org> Date: Sat Aug 13 17:43:03 2016 +0200Correct comment According to C++11 rules, static locals are thread safe for the first-time initialization. See also: http://stackoverflow.com/questions/12302057/c11-safe-double-checked-locking-for-lazy-initialization-possible --- src/graphics/PreviewLoader.cpp | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/graphics/PreviewLoader.cpp b/src/graphics/PreviewLoader.cpp index 88f49b0..f3bf437 100644 --- a/src/graphics/PreviewLoader.cpp +++ b/src/graphics/PreviewLoader.cpp @@ -102,7 +102,7 @@ lyx::Converter const * setConverter(string const & from) << "\" format has been defined."); }); #else - // This is not thread-safe. + // This is also thread-safe according to §6.7.4 of the C++11 standard. static bool first = true; if (first) { first = false;
I think the threading issue here is that the static variable is used for synchronizing the calls in the subsequent line. Maybe what you mean instead by "thread-safe" is that (short of having a drop-in replacement such as call_once) we do not want to spend so much energy in this problem because its effect would be trivial. Saying so in a comment would be helpful for future people reviewing the use of statics in the code. Another thing I was not sure about is whether it was really intended that it will only output one error message independently of the value of "from". But then I see that it is only ever called for from="lyxpreview".
