Re: Cast trap with INI entries compiling C++ extension

On 29/09/11 14:14, Olivier Favre wrote:

Hi everyone, I've been developing a PHP extension for internal needs. We're using C++, by using PHP_REQUIRE_CXX() in config.m4. I'm using debian sid 64bits, with the package php5-dev-5.3.8-2 (against which the patch below has been created). (...)

My point is that there is a problem if it is that easy to trigger a bug with some "natural reflex" to get rid of a warning. I suggest some fixes: * Use strlen() instead of sizeof(). * Use in-macro cast to char[]. * Use const when the string value won't be modified (I'm not talking about the pointer, but its content). In fact, I propose the following changes so that no user (extension writer) code has to change: (...)

We use const char* fields not to trigger the C++ deprecation warning, and we use strlen() to get the size of the string (which is the only normal way anyway), but test for a non NULL value (useless for "name" I guess). By the way, I still return sizeof(NULL) for compatibility, but 0 should probably be a better value. I only tested that change with building my C++ PHP extension, whole PHP recompilation. Best, Using strlen() there forces a runtime call to figure out the string length*, the

sizeof is preferable there. I find the change from char* to const char* acceptable, though. Or at least |char const*, I'm not sure if those values are changed at runtime. I have found in the past some places where a const keyword would be preferable, but was't used. I don't know if there's a rationale for that or is it just "old code". There are functions using the const keyword, so it is not a case of compatibility... * GCC may actually be smart enough to resolve it at compilation time, since it implements strlen() as a builtin. But you obviously can't count on that. I'm not even sure if that's legal C (or from which version). g++ doesn't complain, but with your patch of adding strlen(), I think gcc gives (on C files) the following warning:

warning: initializer element is not a constant expression

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