c-preprocessor

问题 I'm trying to assign a value to a char** variable. In my foo.h I've defined a couple of variables such as #define APIOCTET int #define APILONG long #define APICHAR char #define APISTRING char* Now in my foo.cpp I'm tryng to use a method where APILONG apiInitialize(APISTRING filePath, APISTRING* outputString) { //open text file to where output will be printed //do other stuff, etc.. //return result; } I'd like to assign a value to my APISTRING* outputString but I just can't figure out how to

问题 In the "Apple LLVM 7.0 - Preprocessing" section under the "Build Settings" tab, I've defined a Preprocessor Macros as: STR(arg)=#arg HUBNAME=STR("myhub") HUBLISTENACCESS=STR("Endpoint=sb://abc-xyz.servicebus.windows.net/;SharedAccessKeyName=DefaultListenSharedAccessSignature;SharedAccessKey=JKLMNOP=") In my code, I'm trying to refer to the value of HUBLISTENACCESS as a string: SBNotificationHub* hub = [[SBNotificationHub alloc] initWithConnectionString:@HUBLISTENACCESS notificationHubPath:

问题 Older code in our application contains calls to malloc , realloc and free . With our updated code, our own implementations are called instead of the standard runtime ones. Examples are shown below, #define malloc(s) OurMalloc(s) #define free(p) OurFree(p) This works fine for the updated code and for the newer C++ code we simply implement global new and delete operators, so the C++ solution is 'cleaner'. The problem is that we now have to include a 3rd party library, which has classes that

问题 I have a header file which overrides malloc with a macro. Using add_definitions(-include ../include/failing-malloc-test.h) I'm able to force cmake to include this header file in all targets. The problem is that I only want to have my header file included in some targets(test targets and so on). I tried achieving this using target_compile_definition , but I couldn't achieve the same effect, because target_compile_definition seems to work different than add_definitions . Currently the only

问题 How to get preprocessed C++ code from DevC++ under Windows XP? I've read about creating gcc -E file.cpp file, but I still can't connect the dots, how to run this file? After I've compiled it everything went as usual. 回答1: You simply can't 'run' a preprocessed file. You can just compile and run it, or inspect it for what the preprocessor produced. E.g. when using GCC you can run gcc file.cpp -E <all preprocessor options as set from the IDE> -o file_preprocessed.cpp to get the file_preprocessed

问题 I have a C library (callable from C and C++ code) which handles invalid input by simply exiting. It looks like this #ifdef __cplusplus extern "C" { #endif void exitWithError(const char* func) { printf("woopsie in %s", func); exit(1); } void myfunc(int i) { if (i < 0) exitWithError(__func__); } #ifdef __cplusplus } #endif This library is compiled in "C mode", even when linked with C++ code. I.e. using g++ -x c <abovelibrary.c> I'm using this library in C++ code, and desire it to throw an

问题 It is convenient to use unique error codes that the user will see on an error. This will make it easier to locate the origin of the error for the developer (just do a search in the source code for the error code), thus saving time. Example: void f() { std::cout << "UNIQUE001 " << "Error : The query failed" << std::endl; } void g() { f(); } int main() { g(); return 0; } In the example, the user reports the error ("UNIQUE001 Error : The query failed"). The developer just does a project-wide

问题 For example, there is the source: void func1() { func3(); if(qqq) { func2(); } func4( ); } It should be transformed to: void func1() { MYMACRO func3(); MYMACRO if(qqq) { MYMACRO func2(); MYMACRO } MYMACRO func4( ); MYMACRO } I.e. to insert "MYMACRO\n" at the end of each line where statement can be, only inside functions. How to do it easily? Should I use regular expressions? What tools should I use? For example, can gcc output all line numbers of all statement begins (or ends) inside

问题 For example, there is the source: void func1() { func3(); if(qqq) { func2(); } func4( ); } It should be transformed to: void func1() { MYMACRO func3(); MYMACRO if(qqq) { MYMACRO func2(); MYMACRO } MYMACRO func4( ); MYMACRO } I.e. to insert "MYMACRO\n" at the end of each line where statement can be, only inside functions. How to do it easily? Should I use regular expressions? What tools should I use? For example, can gcc output all line numbers of all statement begins (or ends) inside

问题 I have the following code #define PROC_ADD void main(void) { while(1) { #ifdef PROC_ADD // Do this code here then undefined it to run the code in the else // processing work #undef PROC_ADD #else // now that PROC_ADD has been undefined run this code // processing work #endif } } However, it will run the code. But it won't run the code in the else after the PROC_ADD has been undefined. I think the reason could be that you can only define and undefine at compile time, and not at run-time.