c-preprocessor

X32 allows one to write programs using 32-bit integers, longs and pointers that run on x86_64 processors. Using X32 has a number of benefits under certain use cases. (X32 is different than X86 or X64; see Difference between x86, x32, and x64 architectures for more details). It appears some Windows Enterprise Server supports X32, but I'm having trouble finding more information on it. That's based on some Intel PDFs, like Intel® Xeon® Processor E5-2400 Series-based Platforms for Intelligent Systems : Microsoft's documentation on Predefined Macros lists the usual suspect, like _M_X64 and _M_AMD64

Is it possible to expand a macro which accepts multiple arguments to a different macro if first argument is not the expected value E.g int main() { PRINT(2, "%d%d\n", i, j); //should expand to syslog(2, "%d%d\n", i, j) PRINT("%d%d\n", i, j); //arg1 which is expected to be an int is not preset. /* This should expand differently may be to a default level say 3. syslog(3, "%d%d\n", i,j); */ } I would have tried this kind of over loading if I knew total number of args. I really recommend to write two separate macros for this, just as you would write two differently named functions for the two

Let's say I have a header file with a class that uses std::string . #include <string> class Foo { std::string Bar; public: // ... } The user of this header file might not want std::string to be included in his/her project. So, how do I limit the inclusion to just the header file? The user of your class must include <string> , otherwise their compiler will not know how big a Foo object is (and if Foo 's constructors/destructors are defined inline, then the compiler also won't know what constructor/destructor to call for the string member). This is indeed an irritating side-effect of the C++

I made a generic vector in C using macros. Is the concept viable or do I get a one-way trip to the bonfire for even thinking about it? #ifndef VECTOR_H #define VECTOR_H #define vector_at(vector, pos) ((vector).data[pos]) #define VECTOR_DEFINITION(type)\ typedef struct {\ size_t size;\ size_t capacity;\ type *data;\ } vector_ ## type ## _t;\ void vector_ ## type ## _reserve(vector_ ## type ## _t *vector, size_t size) {\ size_t capacity = 1;\ while (capacity < size) capacity *= 2;\ if (size == 0) capacity = 0;\ if (capacity != vector->capacity)\ {\ vector->capacity = capacity;\ if (size == 0) {\

I have difficulty understanding how rewriting rules are applied by the C preprocessor in the following context. I have the following macros: #define _A(x) "A" _##x #define _B(x) "B" _##x #define X(x) _##x The idea is that each of these macros uses the concatenation to create a new expression, which can itself be a macro — if its a macro, I'd like it to be expanded: Now, the following expands just like I expect: X(x) expands to _x X(A(x)) expands to "A" _x X(A(B(x))) expands to "A" "B" _x However, once the same macro is used more then once, the expansion stops: X(A(A(x))) expands to "A" _A(x),

I need to disable a warning that originates inside the macro '__LOG_W' in following code. To do that, I wrapped this macro inside another macro 'LOG_W' and disabled the warning '-Wold-style-cast' with in that. Then in the code I used the LOG_W instead. However I still get the warning and unable to find out why. Any pointers appreciated. #define LOG_W(expr)\ _Pragma("GCC diagnostic push")\ _Pragma("GCC diagnostic ignored \"-Wold-style-cast\"")\ __LOG_W(DEF, UNKNOWN, expr);\ _Pragma("GCC diagnostic pop") 来源： https://stackoverflow.com/questions/24681881/how-to-put-a-warning-disable-pragma-inside

So, I'm working on translating my C++ app into multiple languages. What I'm currently using is something like: #define TR(x) (lookupTranslatedString( currentLocale(), x )) wcout << TR(L"This phrase is in English") << endl; The translations are from a CSV file which maps the english string to the translated string. "This phrase is in English","Nasa Tagalog itong pagsabi" This is simplified, but that's the basic idea. My question is about generating the list of English phrases that need to be translated. I just need the CSV with all the english phrases, and blank translated phrases. I was hoping

Is there any way to change a preprocessor value like: #define XValue 50 in Objective-C? If you mean changing it during runtime, then no, as XValue is replaced with 50 before compilation. If you mean changing it in the compilation, then yes, using #undef and #define . Example: XValue = 30; // NOT ALLOWED #undef XValue // ALLOWED #define XValue 30 #undef XValue #define XValue 100 What about: int global_mutable_value = 50; #define XValue global_mutable_value Or just int XValue = 50; You don't say why you want XValue to be a macro, so we can't tell whether your intentions for it would be satisfied