2013/7/3 Brad King <brad.k...@kitware.com>: > On 7/3/2013 11:09 AM, Vadim Zhukov wrote: >> I'm an OpenBSD developer, working mostly on porting software. Most of >> my work is related to CMake-based land, including modern KDE and some >> other Qt4-based stuff. > > Great, thanks for coming to us. > >> Here is a module I constructed a few months ago. It's helpful for >> programs that want to use GNU-style backtrace(3) routine, which could >> be found in different libraries and be declared in different headers >> across OSes outta there. > > Thanks for working on this. It looks similar to FindThreads in that > the results could be builtin to the system libraries or in one of > several other vendor-specific libraries. Don't model the module after > FindThreads though as that is one of the oldest modules and does not > fully use modern conventions. > > The BACKTRACE_INCLUDE_DIR and BACKTRACE_LIBRARY variables should > not be documented as results that consuming projects should use > directly. They are inputs to the module that end users edit in > the cache. The results go in BACKTRACE_INCLUDE_DIRS and > BACKTRACE_LIBRARIES. Look at how FindProtobuf.cmake separates > the list of variables in its documentation, for example.
Thank you, that was exactly info I was looking for!
> The line
>
> set(BACKTRACE_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
>
> looks a bit strange to me. The CMAKE_REQUIRED_LIBRARIES variable
> is an input to the check_* APIs and should not be depended upon
> or used by a find module. When calling check_symbol_exists you
> should set CMAKE_REQUIRED_* to known values not depending on the
> calling context. In the case that some non-standard/non-system
> library is needed to provide the symbol it should be set by the
> user through the BACKTRACE_LIBRARY code path.
Yes, I was not sure if this should be done this way either. Other variants are:
1. find_library("c") - not as stupid as it looks from the first time,
because C++ compiler could be called with -nostdlib, for example (and
this was the reason for inclusion of CMAKE_REQUIRED_LIBRARIES
initially);
2. Just make sure BACKTRACE_LIBRARIES is empty: if the developer wants
to shoot himself in the foot with -nostdlib, then he's responsible for
the all consequences; and if he wants to avoid -lc, well, he'll
successfully avoid it.
I'd go with either way. For this try I choosed (2).
> Otherwise, the module looks like a great start!
Thank you for review. I'm sending updated module now. Aside tweaks
based on your input, I realized that there should be a way for the
user to specify BACKTRACE_HEADER, too. I hope that I did not
overcomplicate things.
Checked with the Clementine on OpenBSD-CURRENT.
--
WBR,
Vadim Zhukov
FindBacktrace.cmake
Description: Binary data
-- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://public.kitware.com/cgi-bin/mailman/listinfo/cmake-developers
