I am trying to add a preprocessor definition so that a value is only defined while a certain project is building, then it becomes undefined. I have gone into my project properties -> preprocessor -> preprocessor definitions. In here, I typed #define PROJECTNAME_EXPORT, in hopes that I could call #ifdef PROJECTNAME_EXPORT throughout tha...
How can I tell m4's patsubstr to replace all newlines in a string with a space? I've tried: patsubst(MULTI_LINE_STR_DEFINE,`\n',` ') and patsubst(MULTI_LINE_STR_DEFINE,`\\n',` ') ...
Having seen the advantages of metaprogramming in Ruby and Python, but being bound to lower-level languages like C++ and C for actual work, I'm thinking of manners by which to combine the two. One instance comes in the simple problem for sorting lists of arbitrary structures/classes. For instance: struct s{ int a; int b; }; vector<s...
Hi. I wish to make a cosine table at compile time. Is there a way to do this without hard coding anything? ...
The __FILE__ and __LINE__ macros are built into the C Pre-Processor, and are often used for printing debug output with file names and line numbers. I need something similar, but with just the name of the directory at the end of the path. For instance if my code is in: /home/davidc/some/path/to/some/code/foo/bar I need a macro that will j...
I'd like to code in some preprocessor macros to optionally log some information. For example in the .h //#define ML_DEBUG(x) (x) // flip this bit to do the error logging #define ML_DEBUG(x) (1==1) // flip this bit to silence in the .m I implement like: ML_DEBUG(NSLog(@"Class dealloc: %@", [NSString stringWithCString:object_getClass...
Is there any difference between #include "./test.h" and #include "test.h" for C/C++ preprocessor? ...
I understand that sizeof is an operator, which is evaluated at compile time to an integer constant. But it seem it can not be used in the #if preprocessor directive like: #if 4 == sizeof(int) typedef int Int32; #endif (cygwin-gcc 3.4.4 as well as Visual C++ 6.0 report compile errors) Why is such usage not allowed? ...
Hi, I was reading some code written in C this evening, and at the top of the file was the function-like macro HASH: #define HASH(fp) (((unsigned long)fp)%NHASH) This left me wondering, why would somebody choose to implement a function this way using a function-like macro instead of implementing it as a regular vanilla C function? Wha...
The question is quite clear I think. I'm trying to write a compiler detection header to be able to include in the application information on which compiler was used and which version. This is part of the code I'm using: /* GNU C Compiler Detection */ #elif defined __GNUC__ #ifdef __MINGW32__ #define COMPILER "MinGW GCC %d.%...
I have a need to look at the files Xcode will compile before the preprocessor gets a stab at them. In short, I need to stick a preprocessor in front of the preprocessor. All the Google searching has netted me nada when it comes to details on how to run the default Xcode build process for C-based files after modifying the build rule for ...
Hello everyone! I have an own annotation processor (let's call it MyProcessor) and a project (let's call it MyProject) which uses the processor by passing -processor to javac. Now I need MyProcessor to produce some output and make it available for MyProject. I have following options (and problems): Let MyProcessor write a file to th...
I occasionally write code something like this: // file1.cpp #define DO_THIS 1 #if DO_THIS // stuff #endif During the code development I may switch the definition of DO_THIS between 0 and 1. Recently I had to rearrange my source code and copy some code from one file to another. But I found that I had made a mistake and the two par...
Trying to create a macro which can be used for print debug messages when DEBUG is defined, like the following pseudo code: #define DEBUG 1 #define debug_print(args ...) if (DEBUG) fprintf(stderr, args) How is this accomplished with a macro? ...
Is there a standalone C++ preprocessor? I don't need the compiler/linker, and I'm not able to install a full kit. I'd like to be able to obtain preprocessed version of some headers, using some defines and include paths I provide. EDIT: I can't rely on anything being available. No cl, no gcc, nothing. The least I would need done is some...
Hi, I'm attempting to use the #define directive to change all of "ulong" to "unsigned long". Here is an example: #define ulong unsigned long ulong idCounter = 0; Sadly, I think it ends up replacing ulong with "unsigned", rather than "unsigned long". I tried "#define ulong (unsigned long)", but that didn't worth either. ...
I need to have some lines of code "active" in debug mode only, and ignored in release mode. Is there a way to do something like this: #include <iostream> using namespace std; #ifdef _TEST_ #define _cerr cerr #else #define _cerr // cerr #endif int main() { _cerr << "TEST message" << endl; } So that when _TEST_ is not defined, some...
what is a##b & #a? #define f(a,b) a##b #define g(a) #a #define h(a) g(a) main() { printf("%s\n",h(f(1,2))); //how should I interpret this?? [line 1] printf("%s\n",g(f(1,2))); //and this? [line 2] } How does this program work? the output is 12 f(1, 2) now I understand how a##b & #a work. But...
I have a macro for a character string as follows: #define APPNAME "MyApp" Now I want to construct a wide string using this macro by doing something like: const wchar_t *AppProgID = APPNAME L".Document"; However, this generates a "concatenating mismatched strings" compilation error. Is there a way to convert the APPNAME macro to a ...
Hi, I would like to be able to register my classes within a std::map or a vector, don't think about duplicates and such for now. but I don't want to register it within the class constructor call or any within function of the class, somehow do it outside the class so even if I never instanciate it, I would be able to know that it exists....