I still do it the old way, by defining a macro (XTRACE, below) which correlates to either a no-op or a function call with a variable argument list. Internally, call vsnprintf so you can keep the printf syntax: #include <stdio.h> void XTrace0(LPCTSTR lpszText) { ::OutputDebugString(lpszText); } void XTrace(LPCTSTR lpszFormat, …) { va_list args; va_start(args, lpszFormat); … Read more
Try: #if defined(_WIN32) || defined(_WIN64) // do stuff #endif The defined macro tests whether or not a name is defined and lets you apply logical operators to the result.
Here’s a better C version (from Google’s Chromium project): #define COUNT_OF(x) ((sizeof(x)/sizeof(0[x])) / ((size_t)(!(sizeof(x) % sizeof(0[x]))))) It improves on the array[0] or *array version by using 0[array], which is equivalent to array[0] on plain arrays, but will fail to compile if array happens to be a C++ type that overloads operator[](). The division causes a … Read more
You can use PHP as a C preprocessor. The advantages are: very similiar syntax, so syntax highlighting works. <? and ?> are not used in standard C (with non-standard C, the only thing that gets broken is old GCC extension operator that returns min/max) it’s rich in libraries. it’s turing complete. usage of macros is … Read more
After reading all answers, as well as compiler documentation, I decided I would follow the following standard. For all files, be them project headers or external headers, always use the pattern: #include <namespace/header.hpp> The namespace being at least one directory deep, to avoid collision. Of course, this means that the project directory where the project … Read more
It’s a preprocessor directive that is used (for example) when you expect one of several possible -D symbols to be defined, but none is. #if defined(BUILD_TYPE_NORMAL) # define DEBUG(x) do {;} while (0) /* paranoid-style null code */ #elif defined(BUILD_TYPE_DEBUG) # define DEBUG(x) _debug_trace x /* e.g. DEBUG((_debug_trace args)) */ #else # error “Please specify … Read more
One way (compiler-dependent) is to use dumping after each compiler step. I wrote a small program: template<class T> T square(T n) { return n * n; } int main(void) { square<int>(3); square<float>(3.0); } then: g++ -fdump-rtl-all test.cc This get me a bunch of files. Take a look at (in my case) test.cc.218.dfinish: ;; Function int … Read more
(Edit: See the end for a ready-made solution.) To get an overloaded macro, first we need a macro which selects between several implementations. This part doesn’t use a variadic macro. Then a variadic macro which generically counts its arguments produces a selector. Plugging the argument count into a dispatcher produces an overloaded macro. Caveat: This … Read more
It’s to fix a bug in old versions of Visual C++ (v6.0 and earlier). In the past, Visual C++ had broken scope rules about variables declared inside for statements: // This compiles in old versions of Visual C++, but it is in fact INVALID C++ for(int i = 0; …) { … } for(i = … Read more
I would not do this personally but just come up with unique names. But if you want to do it, one way is to use a combination of if and for: #define FOR_BLOCK(DECL) if(bool _c_ = false) ; else for(DECL;!_c_;_c_=true) You can use it like FOR_BLOCK(GlTranslate t(1.0, 0.0, 0.0)) { FOR_BLOCK(GlTranslate t(1.0, 1.0, 0.0)) { … Read more