It seems we don't need to create a dummy file to list gcc include paths

[ollydbg]

Hi, all.

In the function below

Code

wxArrayString NativeParser::GetGCCCompilerDirs(const wxString &cpp_compiler, const wxString &base)
{
    wxArrayString gcc_compiler_dirs;

    // for starters , only do this for gnu compiler
//    Manager::Get()->GetLogManager()->DebugLog(_T("CompilerID ") + CompilerID);
    //    wxString Command("mingw32-g++ -v -E -x c++ - < nul");
    // specifying "< nul", does not seem to work
    // workaround : create a dummy file (let's hope it does not exist)
    // do the trick only for c++, not needed then for C (since this is a subset of C++)
    wxString DummyFileName = wxFileName::CreateTempFileName(_T("Dummy_z4hsdkl9nf7ba3L9nv41"));
    if(!DummyFileName.IsEmpty())
    {
        // let's construct the command
        wxString Command = cpp_compiler + _T(" -v -E -x c++ ") + DummyFileName;
        // action time  (everything shows up on the error stream
        wxArrayString Output, Errors;
        wxExecute(Command, Output, Errors, wxEXEC_NODISABLE);
        int nCount = Errors.GetCount();
        // the include dir (1 per line) show up between the lines
        // #include <...> search starts here:
        // End of search list
        //   let's hope this does not change too quickly, otherwise we need
        // to adjust our search code (for several versions ...)
        bool bStart = false;
        for(int idxCount = 0; idxCount < nCount; ++idxCount)
        {
            if (!bStart && Errors[idxCount] == _("#include <...> search starts here:"))
            {
                bStart = true;
            }
            else if (bStart && Errors[idxCount] == _("End of search list."))
            {
                bStart = false; // could jump out of for loop if we want
            }
            else if (bStart)
            {
//                Manager::Get()->GetLogManager()->DebugLog("include dir " + Errors[idxCount]);
                // get rid of the leading space (more general : any whitespace)in front
                wxRegEx reg(_T("^[ \t]*(.*)"));
                if(reg.Matches(Errors[idxCount]))
                {
                    wxString out = reg.GetMatch(Errors[idxCount], 1);
                    if(!out.IsEmpty())
                    {
                        wxFileName dir(out);
                        if (NormalizePath(dir,base))
                        {
                            Manager::Get()->GetLogManager()->DebugLog(_T("Caching GCC dir: ") + dir.GetFullPath());
                            gcc_compiler_dirs.Add(dir.GetFullPath());
                        }
                        else
                        #if wxCHECK_VERSION(2, 9, 0)
                            Manager::Get()->GetLogManager()->DebugLog(F(_T("Error normalizing path: '%s' from '%s'"),out.wx_str(),base.wx_str()));
                        #else
                            Manager::Get()->GetLogManager()->DebugLog(F(_T("Error normalizing path: '%s' from '%s'"),out.c_str(),base.c_str()));
                        #endif
                    }
                }
            }
        } // end for : idx : idxCount
        // clean up our temp file
        ::wxRemoveFile(DummyFileName);
    } // Dummy is open

    return gcc_compiler_dirs;
}

A dummy file will be created to input to the command line like:

mingw32-g++ -v -E -x c++ dummyfilename

So, we need to create a dummyfile and after getting all the include paths, we need to delete this file.


After search on Google for an hour, I found there is a way to avoid this:
See this page:

http://gcc.gnu.org/ml/gcc-help/2004-02/msg00142.html

it use these command, it use a minus sign to replace a dummy file name.

mingw32-g++ -v -E -x c++ -

Sees work fine in MinGW, here is the report:

Code

D:\test>mingw32-g++ -v -E -x c++ -
Using built-in specs.
Target: mingw32
Configured with: ../gcc-4.4.0/configure --prefix=/mingw --build=mingw32 --enable
-languages=c,ada,c++,fortran,objc,obj-c++ --disable-nls --disable-win32-registry
 --disable-werror --enable-threads --disable-symvers --enable-cxx-flags='-fno-fu
nction-sections -fno-data-sections' --enable-fully-dynamic-string --enable-libgo
mp --enable-version-specific-runtime-libs --enable-sjlj-exceptions --with-pkgver
sion='TDM-1 mingw32' --with-bugurl=http://www.tdragon.net/recentgcc/bugs.php
Thread model: win32
gcc version 4.4.0 (TDM-1 mingw32)
COLLECT_GCC_OPTIONS='-v' '-E' '-mtune=i386'
 d:/mingw/bin/../libexec/gcc/mingw32/4.4.0/cc1plus.exe -E -quiet -v -iprefix d:\
mingw\bin\../lib/gcc/mingw32/4.4.0/ - -mtune=i386
ignoring nonexistent directory "d:\mingw\bin\../lib/gcc/mingw32/4.4.0/../../../.
./mingw32/include"
ignoring duplicate directory "d:/mingw/lib/gcc/../../lib/gcc/mingw32/4.4.0/inclu
de/c++"
ignoring duplicate directory "d:/mingw/lib/gcc/../../lib/gcc/mingw32/4.4.0/inclu
de/c++/mingw32"
ignoring duplicate directory "d:/mingw/lib/gcc/../../lib/gcc/mingw32/4.4.0/inclu
de/c++/backward"
ignoring duplicate directory "/mingw/lib/gcc/mingw32/4.4.0/../../../../include"
ignoring duplicate directory "d:/mingw/lib/gcc/../../include"
ignoring duplicate directory "d:/mingw/lib/gcc/../../lib/gcc/mingw32/4.4.0/inclu
de"
ignoring duplicate directory "d:/mingw/lib/gcc/../../lib/gcc/mingw32/4.4.0/inclu
de-fixed"
ignoring nonexistent directory "d:/mingw/lib/gcc/../../lib/gcc/mingw32/4.4.0/../
../../../mingw32/include"
ignoring duplicate directory "/mingw/include"
#include "..." search starts here:
#include <...> search starts here:
 d:\mingw\bin\../lib/gcc/mingw32/4.4.0/include/c++
 d:\mingw\bin\../lib/gcc/mingw32/4.4.0/include/c++/mingw32
 d:\mingw\bin\../lib/gcc/mingw32/4.4.0/include/c++/backward
 d:\mingw\bin\../lib/gcc/mingw32/4.4.0/../../../../include
 d:\mingw\bin\../lib/gcc/mingw32/4.4.0/include
 d:\mingw\bin\../lib/gcc/mingw32/4.4.0/include-fixed
End of search list.

Thanks.

[thomas]

Very nice finding, ollydbg. 

Instead of "-", I would use /dev/null or nul depending on operating system, since otherwise gcc will hang (at least does here). Also, if you already call g++, the -x c++ is not needed.
Now, the question is whether to call gcc or g++, actually it would be nice to always call the "correct" compiler depending on whether you compile C or C++ so include paths would be different for C (which they are in real, too) ... but projects may be mixed, and you don't want to call an external program for every single source file parsed...

[ollydbg]

Oh, Yes, you are right.

In MinGW, I found that if only use "-", then gcc will hang up. So, can this method be used in Windows?

Edit:
I'm sorry, I mis understand your previous message. Now I catch the point fully ,

In Windows, this command works ( no hang up):
mingw32-g++ -v -E -x c++ nul
In Linux, this command works:
mingw32-g++ -v -E -x c++ /dev/null


In Linux, using "/dev/null" is better. I also found in the web page below:

http://www.linuxquestions.org/questions/showthread.php?p=2344101#post2344101

For the C or C++ issue, I think g++ is better, because it include all the C headers. 

[ollydbg]

I add a patch in BerliOS

https://developer.berlios.de/patch/index.php?func=detailpatch&patch_id=2783&group_id=5358

I would be happier any dev can test that under Linux.