问题
I'm trying to figure out which of the additions to the algorithm headers are supported by a given implementation (gcc and MSVC would be enough).
The simple way would be to do it the same way as one would do it for core features: check the compiler version and define a macro if a language feature is supported. Unfortunately I cannot find a list that shows the version numbers for either compiler.
Is simply checking for a generic C++0x macro (GXX_EXPERIMENTAL or __cplusplus) enough or should I check the change lists for the compilers and build my macros based on those lists?
http://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.200x
回答1:
Since all compiler vendors provide a nice list of what's available in what version, and you would test the functionality anyways, I would use compiler versions to check for specific features. Or demand the user uses at least a good version, and not worry about it.
__cplusplus is not necessarily a C++0x macro, it tells you nothing. GXX_EXPERIMENTAL has existed since GCC 4.3, so that's pretty useless too.
This one is for GCC.
This one is for MSVC. (mind you: partially implemented means broken)
This one is for Intel.
Here you can find what macros to check against for a specific version of a compiler.
回答2:
As far as I could figure out the only proper solution is to have a build script that tries to compile and run a file that uses the feature and has a runtime assertion. Depending on the outcome have a #define CONFIG_NO_FEATURENAME or similiar in a config file and guard your uses and workaround with a #ifndef.
This way it is possible to check if
- the feature is available
- the feature functions properly (depending on the correctness of the assertion)
来源：https://stackoverflow.com/questions/6095885/checking-for-availability-of-c0x-algorithm-additions