Determining if the Q_WS_X11 exist failed with the following output: Microsoft (R) Visual Studio Version 8.0.50727.42. Copyright (C) Microsoft Corp 1984-2005. All rights reserved. 1>------ Build started: Project: cmTryCompileExec, Configuration: Debug Win32 ------ 1>Compiling... 1>Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 14.00.50727.42 for 80x86 1>Copyright (C) Microsoft Corporation. All rights reserved. 1>cl /Od /I "C:\Qt\4.3.3\include" /D "WIN32" /D "_WINDOWS" /D "_DEBUG" /D "CMAKE_INTDIR=\"Debug\"" /D "_MBCS" /FD /EHsc /RTC1 /MDd /Fo"cmTryCompileExec.dir\Debug\\" /Fd"D:/Development/Builds/HelloWorld/CMakeFiles/CMakeTmp/Debug/cmTryCompileExec.pdb" /W3 /c /Zi /TC /Zm1000 1> .\CheckSymbolExists.c 1>CheckSymbolExists.c 1>.\CheckSymbolExists.c(8) : error C2065: 'Q_WS_X11' : undeclared identifier 1>Build log was saved at "file://d:\Development\Builds\HelloWorld\CMakeFiles\CMakeTmp\cmTryCompileExec.dir\Debug\BuildLog.htm" 1>cmTryCompileExec - 1 error(s), 0 warning(s) ========== Build: 0 succeeded, 1 failed, 1 up-to-date, 0 skipped ========== File D:/Development/Builds/HelloWorld/CMakeFiles/CMakeTmp/CheckSymbolExists.c: /* */ #include void cmakeRequireSymbol(int dummy,...){(void)dummy;} int main() { #ifndef Q_WS_X11 cmakeRequireSymbol(0,&Q_WS_X11); #endif return 0; } Determining if the Q_WS_QWS exist failed with the following output: Microsoft (R) Visual Studio Version 8.0.50727.42. Copyright (C) Microsoft Corp 1984-2005. All rights reserved. 1>------ Build started: Project: cmTryCompileExec, Configuration: Debug Win32 ------ 1>Compiling... 1>Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 14.00.50727.42 for 80x86 1>Copyright (C) Microsoft Corporation. All rights reserved. 1>cl /Od /I "C:\Qt\4.3.3\include" /D "WIN32" /D "_WINDOWS" /D "_DEBUG" /D "CMAKE_INTDIR=\"Debug\"" /D "_MBCS" /FD /EHsc /RTC1 /MDd /Fo"cmTryCompileExec.dir\Debug\\" /Fd"D:/Development/Builds/HelloWorld/CMakeFiles/CMakeTmp/Debug/cmTryCompileExec.pdb" /W3 /c /Zi /TC /Zm1000 1> .\CheckSymbolExists.c 1>CheckSymbolExists.c 1>.\CheckSymbolExists.c(8) : error C2065: 'Q_WS_QWS' : undeclared identifier 1>Build log was saved at "file://d:\Development\Builds\HelloWorld\CMakeFiles\CMakeTmp\cmTryCompileExec.dir\Debug\BuildLog.htm" 1>cmTryCompileExec - 1 error(s), 0 warning(s) ========== Build: 0 succeeded, 1 failed, 1 up-to-date, 0 skipped ========== File D:/Development/Builds/HelloWorld/CMakeFiles/CMakeTmp/CheckSymbolExists.c: /* */ #include void cmakeRequireSymbol(int dummy,...){(void)dummy;} int main() { #ifndef Q_WS_QWS cmakeRequireSymbol(0,&Q_WS_QWS); #endif return 0; } Determining if the Q_WS_MAC exist failed with the following output: Microsoft (R) Visual Studio Version 8.0.50727.42. Copyright (C) Microsoft Corp 1984-2005. All rights reserved. 1>------ Build started: Project: cmTryCompileExec, Configuration: Debug Win32 ------ 1>Compiling... 1>Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 14.00.50727.42 for 80x86 1>Copyright (C) Microsoft Corporation. All rights reserved. 1>cl /Od /I "C:\Qt\4.3.3\include" /D "WIN32" /D "_WINDOWS" /D "_DEBUG" /D "CMAKE_INTDIR=\"Debug\"" /D "_MBCS" /FD /EHsc /RTC1 /MDd /Fo"cmTryCompileExec.dir\Debug\\" /Fd"D:/Development/Builds/HelloWorld/CMakeFiles/CMakeTmp/Debug/cmTryCompileExec.pdb" /W3 /c /Zi /TC /Zm1000 1> .\CheckSymbolExists.c 1>CheckSymbolExists.c 1>.\CheckSymbolExists.c(8) : error C2065: 'Q_WS_MAC' : undeclared identifier 1>Build log was saved at "file://d:\Development\Builds\HelloWorld\CMakeFiles\CMakeTmp\cmTryCompileExec.dir\Debug\BuildLog.htm" 1>cmTryCompileExec - 1 error(s), 0 warning(s) ========== Build: 0 succeeded, 1 failed, 1 up-to-date, 0 skipped ========== File D:/Development/Builds/HelloWorld/CMakeFiles/CMakeTmp/CheckSymbolExists.c: /* */ #include void cmakeRequireSymbol(int dummy,...){(void)dummy;} int main() { #ifndef Q_WS_MAC cmakeRequireSymbol(0,&Q_WS_MAC); #endif return 0; }