Please look at the following file: (it is a complete file)
#ifndef TEES_ALGORITHM_LIBRARY_WRAPPER_H
#define TEES_ALGORITHM_LIBRARY_WRAPPER_H
#ifdef _TEES_COMPILE_AS_LIB
#include <dfa\Includes\DFC_algorithms.hpp>
#include <DFA\FuzzyClassifier\FuzzyAlgorithmIntialization\InitFuzzyAlgorithm.hpp>
typedef teesalgorithm::tees_fuzzy_algorithms algorithms_switchyard_class;
#else
#include <DFA\Includes\commercial_algorithms.hpp>
//An incomplete class to hide implementation
class algorithms_switchyard_class;
#endif
class AlgorithmLibraryWrapper {
algorithms_switchyard_class * algorithmPtr_;
typedef teesalgorithm::tees_paramObj paramObj_type;
typedef teesalgorithm::tees_errorObj errorObj_type;
typedef teesalgorithm::tees_statusObj statusObj_type;
typedef teesalgorithm::tees_dataObj dataObj_type;
typedef teesalgorithm::tees_outputObj outputObj_type;
public:
AlgorithmLibraryWrapper(const std::string& sAlgName, paramObj_type& paramObj, errorObj_type& errObj, statusObj_type& statusObj, const char* sFilePath);
static bool dataReader(const std::string& sFileName, dataObj_type& dataObj, errorObj_type& errObj, statusObj_type& statusObj);
bool runalgorithm(const dataObj_type& dataObj, outputObj_type& outObj, errorObj_type& errObj, statusObj_type& statusObj);
~AlgorithmLibraryWrapper();
};
#ifdef _TEES_USE_COMPILED_ALGORITHM_LIB
# ifdef _MSC_VER
#if _MSC_VER < 1400 // If VC 2003
#ifdef _DEBUG
#error No AlgorithmLibWrapper libraries compiled for this version of VC
#else
#error No AlgorithmLibWrapper libraries compiled for this version of VC
#endif
#elif defined(UNDER_CE) // Win CE
#ifdef _DEBUG
#pragma comment( lib, "AlgorithmLibWrapperCEd" )
#else
#pragma comment( lib, "AlgorithmLibWrapperCE" )
#endif
#else // If VC 2005
#ifdef _DEBUG
#pragma comment( lib, "AlgorithmLibWrapperd" )
#else
#pragma comment( lib, "AlgorithmLibWrapper" )
#endif
#endif
#endif
#endif
#endif //TEES_ALGORITHM_LIBRARY_WRAPPER_H
I am getting the following errors; I don't know why. I manually counted the preprocessor directives also.
AlgorithmLibraryWrapper.hpp:10:1: unterminated #ifdef
AlgorithmLibraryWrapper.hpp:7:1: unterminated #ifndef
I am using the poor vxWorks gcc compiler. Please let me know if the fault is mine or the compiler's.
It could be that the problem is in the included files (if there actually are unbalaced #if/#endifs.
I would try preprocessing with another compiler. You can use gcc for that, doesn't matter it wouldn't compile. Just get gcc (or MinGW if you're on Windows) and run
cpp -Iinclude_direcories your_file
Or, if you don't like gcc, get MSVC Express edition. Again, you can preprocess code that even doesn't compile, so no problem with nonworking library etc.
Most compilers have an option that will give you the output from the preprocessor so you can check what it's doing. For example,
gcc -E file.c >file.preproc
will give you the pre-processed source so you can check the balancing of #if against #endif.
At a guess, one of the files you are #including from this one has a mismatched #ifdef/#endif pair. You need to look at all the files (as the preprocesor does), not just this one.
As others have noted, this is most likely due to mismatched include guards.
If the files you are including are under your control (i.e. not part of a 3rd party closed source library), you could consider replacing the #ifndef et. al. guards (which are used to prevent multiple inclusion) with #pragma once. This will eliminate the possibility of having mismatched preprocessor directives.
One caveat of this is that pragma once is non-standard, so it will only work if your compiler supports it.
I have tried to compile your source using vs 6.0 but did not get the error you have mentioned. As others said may be the error is coming from the included header file . For me to get your code compiled i need to comment the above header.
Please check the above header once.
I'd debug this by commenting out sections one by one and trying to identify which section is causing the error.
It could be your compiler does not like the nested #ifdefs or does not interpret the syntax correctly. Maybe it doesn't like the #pragmas.
This is a long shot, but in your source file you have the following line:
# ifdef _MSC_VER
where there is whitespace between the '#' character and the directive name (ifdef). This is valid in C/C++; however, it's not too commonly seen so I wouldn't be very surprised if the odd compiler choked on it.
Related
I am working with emscripten, which uses some macros that VS Code IntelliSense does not like. This is not unusual. So what I'd like to do is this:
#ifdef INTELLISENSE_IS_READING_THIS
#define PROBLEMATIC_MACRO
#endif
That way, I can keep the macros as is but VS code will stop whining.
Sad thing is I remember solving this exact problem in Visual Studio 2017 IntelliSense - with Microsoft's very own resource files - but unfortunately, it appears I did not ask this on stack overflown and instead solved it myself, so now I can't find it anymore.
𝙃𝙖! Found it. Just needed to craft a query that excludes all the questions about IntelliSense NOT reading or defining defines.
This is the way:
#ifdef __INTELLISENSE__
#define EMSCRIPTEN_KEEPALIVE
#endif
And this also works, but may also evaluate in Microsofts compiler:
#ifdef _MSC_VER
#define EMSCRIPTEN_KEEPALIVE
#endif
I found following code in library I'm trying to compile
#ifdef __GNU LesserC__
__attribute__((packed))
#endif
and
#ifdef __GNU LesserG__
#pragma interface
#endif
What the hell is __GNU LesserC__? Why is there the space, #ifdef afaik doesn't support anything like this. I trying googling it but I only found source code using it, no explanation what it is (was) supposed to do.
Most patches I found fix it by
- #ifdef __GNU LesserC__
+ #ifdef __GNU_LesserC__
but I would like to know what this actually is.
Oh, and the library is xbase.
I'm trying to forward calls from my DLL to another DLL. I can't find any documentation about how to do that with MinGW.
Using Visual C++ compiler I would go with:
#pragma comment (linker, "/export:DllInitialize=api.DllInitialize,#2")
Or by using a .def definition file:
EXPORTS
DllInitialize=api.DllInitialize
But none of these work when compiling with MinGW32. I am using Code::Blocks as IDE if it matters. How can I do this with MinGW32?
i am sorry, i added a bit too many double-quotes in the above code. instead it should be this way:
asm (".section .drectve\n\t.ascii \" -export:DllInitialize=api.DllInitialize #2\"");
If you need to use it many times, consider putting it in a macro, e.g.
#ifdef _MSC_VER
#define FORWARDED_EXPORT_WITH_ORDINAL(exp_name, ordinal, target_name) __pragma (comment (linker, "/export:" #exp_name "=" #target_name ",#" #ordinal))
#endif
#ifdef __GNUC__
#define FORWARDED_EXPORT_WITH_ORDINAL(exp_name, ordinal, target_name) asm (".section .drectve\n\t.ascii \" -export:" #exp_name "= " #target_name " #" #ordinal "\"");
#endif
FORWARDED_EXPORT_WITH_ORDINAL(DllInitialize, 2, api.DllInitialize)
FORWARDED_EXPORT_WITH_ORDINAL(my_create_file_a, 100, kernel32.CreateFileA)
you get the idea
here is how you can do it:
#ifdef _MSC_VER
#pragma comment (linker, "/export:DllInitialize=api.DllInitialize,#2")
#endif
#ifdef __GNUC__
asm (".section .drectve\n\t.ascii \" -export:\\\"DllInitialize=api.DllInitialize\\\" #2\"");
#endif
Note that "drectve" is not a typo, thats how it must be written however odd it may seem. By the way, this strange abbreviation is a microsoft's idea, not GCC's.
I see this being done all the time for example in the Linux Kernel. What is the purpose of using the preprocessor commands vs just normal C++ if else block? Is there a speed advantage or something?
A preprocessor changes the C/C++ code before it gets compiled (hence pre processor).
Preprocessor ifs are evaluated at compile-time.
C/C++ ifs are evaluated at run-time.
You can do things that can't be done at run-time.
Adjust code for different platforms or different compilers:
#ifdef __unix__ /* __unix__ is usually defined by compilers targeting Unix systems */
#include <unistd.h>
#elif defined _WIN32 /* _Win32 is usually defined by compilers targeting 32 or 64 bit Windows systems */
#include <windows.h>
#endif
Ensure header file definitions are included only once (equivalent of #pragma once, but more portable):
#ifndef EXAMPLE_H
#define EXAMPLE_H
class Example { ... };
#endif
You can make things faster than at run-time.
void some_debug_function() {
#ifdef DEBUG
printf("Debug!\n");
#endif
}
Now, when compiling with DEBUG not defined (likely a command line parameter to your compiler), any calls to some_debug_function can be optimized away by the compiler.
Preprocessor is run before the compilation pass, so the compiler won't even see anything that was in the not-taken #if branch.
#if DEBUG
int a;
#else
double b;
#endif
gcc -c -DDEBUG=1 file.c will see "int a"
gcc -c file.c will see "double b"
Preprocessor allows you to actually cut out or paste in to your source file, code to be compiled. If its cut out, its gone, its like a comment, does nothing, is not compiled, produces no code in the binary. Devs will often use this technique to add code only in debug build for debugging purposes or for adding or excluding code for specific operating systems.
I work in Visual Studio but my project is for a POSIX-based environment (marmalade sdk). In this project, the release
build is compiled with gcc for ARM but the debug version works on windows and is compiled by MS compiler. Also this environmet has its own implementation of STL and other standard libraries.
Many of these c++ librares have code like this:
#if defined( _MSC_VER )
#include <Windows.h>
#else
#include <pthread.h>
#endif
Is it possible to undefine the _MSC_VER macro? - So that the C++ libraries will detect a POSIX system here.
_MSC_VER is (and always should be) defined when compiling with the Microsoft compiler so that it "evaluates to the major and minor number components of the compiler's version number". Therefore, the code is using the wrong macro test, since it will always be defined to some value for your compiler regardless of the Windows environment differences.
Rather than destroy the definition of _MSC_VER (which could lead to other problems if any code really does want to know the compiler version), what you really should do instead is to correct the condition so that a more appropriate macro test is used that distinguishes between the kinds of Windows environments that you might encounter.
See the more complete list of predefined macros you could consider here
You could either replace the condition ...
#if someOtherConditionGoesHere
... or extend it with additional conditions, e.g.
#if defined(_MSC_VER) && someOtherConditionGoesHere
Of course:
#undef _MSC_VER
#if defined( _MSC_VER )
#include <Windows.h>
#else
#include <pthread.h>
#endif
Or, #undef it before you include the file where _MSC_VER is used.