问题
I'm building a commercial app, and we are using some GPL code to help us along.
How can I add #warning or #error statements so that when the code is built for debug, it warns, but when we build for release it throws errors?
I can do:
#warning this code is released under a CCL licensing scheme, see Source_Code_License.rtf
#warning this code is not LGPL-compliant
#warning this code was copied verbatim from a GP Licensed file
at the beginning of files, but can I do better? Is there a better way of tagging a file if it's included?
I'm using Objective-C++ with gcc or clang.
回答1:
Use #pragma message instead.
回答2:
#ifdef SOME_SYMBOL
#error "foobar"
#else
#warning "foobar"
#endif
NDEBUG has a slightly different purpose (controlling assert) and may be #undef and re-defined selectively (reincluding assert.h to effect the change), so it probably wouldn't be the right symbol. But it is a standard macro and could be used.
Note that #error is standard, but #warning is an extension.
来源：https://stackoverflow.com/questions/4168245/create-custom-warning-flags