迁移到MSYS2 与 Qt 工具链注意的几个事情(g++在链接时,符号依赖项查找遵循从左至右的顺序,但qmake会自动合并造成错误。使用脚本给Mingw32-make创造出一个局部的VC编译环境)
Microsoft Visual Studio 2015社区版提供了强大的开发体验,且 Qt 提供了预编译版本。然而,由于客户提出兼容Windows XP ~ Windows 8.1 这样宽泛的环境要求,使得我们不得不考虑更换工具链。经过反复对比测试,在Mingw32, Cygwin, MSYS2, Visual Studio 2010几个工具链中,综合性能、未来的可持续性、中文支持以及第三方库支持(比如qwt),认为MSYS2较为合适。在后续复杂的迁移过程中,基本是平顺的,但也遇到了一些问题,这里做个记录。
1、ActiveQt COM/OLE 支持有问题,需要额外设置编译参数
我们有个子项目需要生成一个ActiveX控件,使用到了 QAxContainer模块。在编译时,报告了上百个编译错误,提示找不到 libole32.a, libuuid.a 等库中包含的符号。经过简单分析,特别是MakeFile中的编译器指令提示,MSYS2没有正确处理ActiveQt的链接选项。具体说来,由于g++在链接时,符号依赖项查找遵循从左至右的顺序,如果设置不当,会导致诡异的链接错误,请参考这篇文章。
知道了这个问题,我们手工在pro文件中加入下面的内容:
- LIBS += -lQt5AxServer -lQt5AxBase -lole32 -loleaut32 -luser32 -lgdi32 -ladvapi32 -luuid
错误竟然依旧!继续观察qmake出来的MakeFile,发现-lQt5Ax* 都被放到了最后。一拍脑袋,怎么忘记了, qmake 在产生Makefile对相同名称的库进行合并,会改变其原有的顺序这个坑~!于是,把需要使用 QAxServer 模块的工程改成这样:
- win32-g++{
- CONFIG += no_lflags_merge
- LIBS += -lQt5AxServer -lQt5AxBase -lole32 -loleaut32 -luser32 -lgdi32 -ladvapi32 -luuid
- }
把需要使用 QAxContainer 模块的工程改成这样:
- win32-g++{
- CONFIG += no_lflags_merge
- LIBS += -lQt5AxContainer -lQt5AxBase -lole32 -loleaut32 -luser32 -lgdi32 -ladvapi32 -luuid
- }
no_lflags_merge 表示不进行库合并和排序(排序是合并的副作用,估计内部合并时用了类似set 之类的类stl容器),这样,Makfile中,Qt5Ax*库就位于系统库之前了!这一点在Qt官方Mingw32安装版里是调整好了的。
修改后,链接通过,但是,Post Link 流程出错。
2. 解决参数转译符冲突
链接后,第一个问题是无法生成IDL文件。考察编译输出命令行,发现对 idc.exe 调用时,传参数使用的是 windows 参数转译符 "/"。然而,在msys2环境里,"/"不是unix命令行的合法参数转译符,应该用“-”(减号)才对。不要紧,这个编译后事件的命令全部存储在 mingw32(64)/share/qt5/mkspecs/features/win32/idcidl.prf 里。这个文件的内容如下:
- ...
- !qaxserver_no_postlink {
- !isEmpty(QMAKE_POST_LINK):QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_NEWLINE)
- QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_IDC $ ${ACTIVEQT_TARGET} /idl $ ${ACTIVEQT_OUTPUT}.idl -version $ ${ACTIVEQT_VERSION}$ ${ACTIVEQT_NEWLINE})
- !isEmpty(RC_FILE) {
- QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_IDL "$ ${ACTIVEQT_OUTPUT}.idl" /nologo /tlb "$ ${ACTIVEQT_OUTPUT}.tlb"$ $ACTIVEQT_NEWLINE)
- QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_IDC $ ${ACTIVEQT_TARGET} -tlb $ ${ACTIVEQT_OUTPUT}.tlb$ $ACTIVEQT_NEWLINE)
- } else {
- QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_IDL "$ ${ACTIVEQT_OUTPUT}.idl" /nologo /tlb "$ ${ACTIVEQT_TLBOUT}"$ $ACTIVEQT_NEWLINE)
- message("No rc-file linked into project; type library will be a separate file.")
- }
- !qaxserver_no_register: \
- QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_IDC $ ${ACTIVEQT_TARGET} /regserver)
- QMAKE_CLEAN += $ ${ACTIVEQT_OUTPUT}.idl $ ${ACTIVEQT_OUTPUT}.tlb
- }
二话不说,全部改为"-"
- !qaxserver_no_postlink {
- !isEmpty(QMAKE_POST_LINK):QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_NEWLINE)
- QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_IDC $ ${ACTIVEQT_TARGET} -idl $ ${ACTIVEQT_OUTPUT}.idl -version $ ${ACTIVEQT_VERSION}$ ${ACTIVEQT_NEWLINE})
- !isEmpty(RC_FILE) {
- QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_IDL "$ ${ACTIVEQT_OUTPUT}.idl" -nologo -tlb "$ ${ACTIVEQT_OUTPUT}.tlb"$ $ACTIVEQT_NEWLINE)
- QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_IDC $ ${ACTIVEQT_TARGET} -tlb $ ${ACTIVEQT_OUTPUT}.tlb$ $ACTIVEQT_NEWLINE)
- } else {
- QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_IDL "$ ${ACTIVEQT_OUTPUT}.idl" -nologo -tlb "$ ${ACTIVEQT_TLBOUT}"$ $ACTIVEQT_NEWLINE)
- message("No rc-file linked into project; type library will be a separate file.")
- }
- !qaxserver_no_register: \
- QMAKE_POST_LINK += $ $quote($ $ACTIVEQT_IDC $ ${ACTIVEQT_TARGET} -regserver)
- QMAKE_CLEAN += $ ${ACTIVEQT_OUTPUT}.idl $ ${ACTIVEQT_OUTPUT}.tlb
- }
修改后,再次重新编译(要重新编译才能触发编译后事件),idl 顺利产生。
可是,接着问题又大了,msys2 的工具链里没有 midl.exe。这个工具是windows SDK 的一部分,且需要Visual C++的 cl.exe。先是尝试在PATH里加入路径,但没有成功。除非彻底加入vcvars32.bat的所有设置,否则无法通过。这个问题有办法:
3. 为Mingw32 环境提供midl.exe支持
前文书,midl.exe 是 windows SDK中的工具,这个工具依赖Visual C++编译器。然而,在MingW工具链中,默认是无法调用VC编译器的。为了给Mingw32-make创造出一个局部的VC编译环境,新建一个简单的控制台外壳,名字也叫“midl.exe”,在内部调用 vcvars32.bat并把命令行参数传给真正的 midl.exe即可:
pro文件,控制台Qt应用:
- QT += core
- QT -= gui
- CONFIG += c++11
- TARGET = midl
- CONFIG += console
- CONFIG -= app_bundle
- TEMPLATE = app
- SOURCES += main.cpp
唯一的代码文件,main.cpp:
- #include <QCoreApplication>
- #include <QString>
- #include <QSettings>
- #include <QDir>
- #include <QProcess>
- #include <QStringList>
- #include <QDebug>
- #include <stdlib.h>
- int main(int argc, char *argv[])
- {
- QCoreApplication a(argc, argv);
- QString exeName = a.applicationName();
- //0. the exe name and ini filename should be stored together.
- QString iniFile = a.applicationFilePath() + ".ini";
- QSettings settings(iniFile,QSettings::IniFormat);
- //1.get the current directory
- QString strCurrentDir = QDir::current().absolutePath();
- //2.get the visual studio vcvars32 path and raw EXE path
- QString vcvarsPath = settings.value("SETTINGS/VCVARS","D:\\Microsoft Visual Studio 10.0\\VC\\bin\\vcvars32.bat")
- .toString();
- QString exeDir = settings.value("SETTINGS/EXEDIR","C:\\Program Files (x86)\\Windows Kits\\8.1\\bin\\x86")
- .toString();
- //3.Make the cmd target
- QString cmd ;
- //3.1. call vc vars to
- // cmd += " && ";
- cmd += "CALL ";
- cmd += "\"" + vcvarsPath + "\"";
- //3.2. chdir back to current
- cmd += " && ";
- cmd += "CD /D \"" + strCurrentDir.replace("/","\\") + "\"";
- //3.3. call exeName with args
- cmd += " && ";
- cmd += "\"" + exeDir + "\\" + exeName + "\" ";
- for(int i=1;i<argc;++i)
- cmd += argv[i] + QString(" ");
- settings.setValue("SETTINGS/VCVARS",vcvarsPath);
- settings.setValue("SETTINGS/EXEDIR",exeDir);
- //4. display and exe the cmd
- puts(cmd.toStdString().c_str());
- int ret = system(cmd.toStdString().c_str());
- a.exit(0);
- return ret;
- }
默认的VC配置可能和实际的不符合,不要紧,只要在 midl.exe (壳子)同文件夹下设置midl.exe.ini即可:
- [SETTINGS]
- VCVARS=D:\\Microsoft Visual Studio 10.0\\VC\\bin\\vcvars32.bat
- EXEDIR=C:\\Program Files (x86)\\Windows Kits\\8.1\\bin\\x86
修改这个参数即可。VCVARS即是vc编译器批处理文件的位置,EXEDIR是真的midl.exe的文件夹。
4. 试试看!
二话不说,开始编译,OK!
- g++ -Wl,-s -shared -Wl,-subsystem,windows -mthreads -Wl,--out-implib,../bin/libqtaxviewer_planetosm.dll.a -Wl,../../qtv.planet/qtviewer_planetosm/qtaxviewer_planetosm.def -o ../bin/qtaxviewer_planetosm.dll object_script.qtaxviewer_planetosm.Release -lglu32 -lopengl32 -lgdi32 -luser32 -lQt5AxServer -lQt5AxBase -lole32 -loleaut32 -luser32 -lgdi32 -ladvapi32 -luuid -lQt5AxServer -lQt5AxBase -lQt5Widgets -lQt5Gui -lQt5Network -lQt5Core
- /D/msys64/mingw32/bin/idc.exe ../bin/qtaxviewer_planetosm.dll -idl release//qtaxviewer_planetosm.idl -version 1.0
- release\\qtaxviewer_planetosm.idl
- midl release//qtaxviewer_planetosm.idl -nologo -tlb release//qtaxviewer_planetosm.tlb
- Setting environment for using Microsoft Visual Studio 2010 x86 tools.
- Processing release\\qtaxviewer_planetosm.idl
- qtaxviewer_planetosm.idl
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\ocidl.idl
- ocidl.idl
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\oleidl.idl
- oleidl.idl
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\objidl.idl
- objidl.idl
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\unknwn.idl
- unknwn.idl
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\wtypes.idl
- wtypes.idl
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\basetsd.h
- basetsd.h
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\guiddef.h
- guiddef.h
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\oaidl.idl
- oaidl.idl
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\servprov.idl
- servprov.idl
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\urlmon.idl
- urlmon.idl
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\msxml.idl
- msxml.idl
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\oaidl.acf
- oaidl.acf
- Processing C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\include\ocidl.acf
- ocidl.acf
- CALL "D:\Microsoft Visual Studio 10.0\VC\bin\vcvars32.bat" && CD /D "D:\documents\Qt\build-qplanetosm-Desktop_Qt_MinGW_w64_32bit_MSYS2-Release\qtviewer_planetosm" && "C:\Program Files (x86)\Windows Kits\8.1\bin\x86\midl" release//qtaxviewer_planetosm.idl -nologo -tlb release//qtaxviewer_planetosm.tlb
- /D/msys64/mingw32/bin/idc.exe ../bin/qtaxviewer_planetosm.dll -tlb release//qtaxviewer_planetosm.tlb
- Type library attached to D:\documents\Qt\build-qplanetosm-Desktop_Qt_MinGW_w64_32bit_MSYS2-Release\bin\qtaxviewer_planetosm.dll.
- /D/msys64/mingw32/bin/idc.exe ../bin/qtaxviewer_planetosm.dll -regserver
- Server registered successfully!
- mingw32-make[2]: Leaving directory 'D:/documents/Qt/build-qplanetosm-Desktop_Qt_MinGW_w64_32bit_MSYS2-Release/qtviewer_planetosm'
- mingw32-make[1]: Leaving directory 'D:/documents/Qt/build-qplanetosm-Desktop_Qt_MinGW_w64_32bit_MSYS2-Release/qtviewer_planetosm'
- 09:57:52: 进程"D:\msys64\mingw32\bin\mingw32-make.exe"正常退出。
- 09:57:52: Elapsed time: 01:26.
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