Add option of TRY_COMPILE to store the output of compilation so that if the output fails you can display it or store it in the file

Source/cmGlobalGenerator.cxx

@@ -141,7 +141,8 @@ void cmGlobalGenerator::LocalGenerate()
 }
 
 int cmGlobalGenerator::TryCompile(const char *, const char *bindir, 
-                                  const char *, const char *target)
+                                  const char *, const char *target,
+                                  std::string *output)
 {
   // now build the test
   std::string makeCommand = 
@@ -157,7 +158,6 @@ int cmGlobalGenerator::TryCompile(const char *, const char *bindir,
   /**
    * Run an executable command and put the stdout in output.
    */
-  std::string output;
   std::string cwd = cmSystemTools::GetCurrentWorkingDirectory();
   cmSystemTools::ChangeDirectory(bindir);
   
@@ -172,7 +172,8 @@ int cmGlobalGenerator::TryCompile(const char *, const char *bindir,
     makeCommand += " all";
     }
   int retVal;
-  if (!cmSystemTools::RunCommand(makeCommand.c_str(), output, retVal, 0, false))
+  
+  if (!cmSystemTools::RunCommand(makeCommand.c_str(), *output, retVal, 0, false))
     {
     cmSystemTools::Error("Generator: execution of make failed.");
     // return to the original directory

Source/cmGlobalGenerator.h

@@ -87,7 +87,8 @@ public:
    * loaded commands, not as part of the usual build process.
    */
   virtual int TryCompile(const char *srcdir, const char *bindir,
-                         const char *projectName, const char *targetName);
+                         const char *projectName, const char *targetName,
+                         std::string *output);
 
   ///! Set the CMake instance
   void SetCMakeInstance(cmake *cm) {

Source/cmMakefile.cxx

@@ -1340,7 +1340,8 @@ void cmMakefile::ExpandSourceListArguments(
 
 int cmMakefile::TryCompile(const char *srcdir, const char *bindir, 
                            const char *projectName, const char *targetName,
-                           const std::vector<std::string> *cmakeArgs)
+                           const std::vector<std::string> *cmakeArgs,
+                           std::string *output)
 {
   // does the binary directory exist ? If not create it...
   if (!cmSystemTools::FileIsDirectory(bindir))
@@ -1409,7 +1410,8 @@ int cmMakefile::TryCompile(const char *srcdir, const char *bindir,
   int ret = 
     m_LocalGenerator->GetGlobalGenerator()->TryCompile(srcdir,bindir,
                                                        projectName, 
-                                                       targetName);
+                                                       targetName,
+                                                       output);
 
   cmSystemTools::ChangeDirectory(cwd.c_str());
   return ret;

Source/cmMakefile.h

@@ -85,7 +85,8 @@ public:
    */
   int TryCompile(const char *srcdir, const char *bindir, 
                  const char *projectName, const char *targetName,
-                 const std::vector<std::string> *cmakeArgs);
+                 const std::vector<std::string> *cmakeArgs,
+                 std::string *output);
     
   /**
    * Specify the makefile generator. This is platform/compiler

Source/cmTryCompileCommand.cxx

@@ -33,7 +33,8 @@ int cmTryCompileCommand::CoreTryCompileCode(
   std::string tmpString;
 
   // do we have a srcfile signature
-  if (argv.size() == 3 || argv[3] == "CMAKE_FLAGS" || argv[3] == "COMPILE_DEFINITIONS")
+  if (argv.size() == 3 || argv[3] == "CMAKE_FLAGS" || argv[3] == "COMPILE_DEFINITIONS" ||
+      argv[3] == "OUTPUT_VARIABLE")
     {
     srcFileSignature = true;
     }
@@ -44,7 +45,8 @@ int cmTryCompileCommand::CoreTryCompileCode(
     {
     if (argv[i] == "CMAKE_FLAGS")
       {
-      for (; i < argv.size() && argv[i] != "COMPILE_DEFINITIONS"; 
+      for (; i < argv.size() && argv[i] != "COMPILE_DEFINITIONS" && 
+             argv[i] != "OUTPUT_VARIABLE"; 
            ++i)
         {
         cmakeFlags.push_back(argv[i]);
@@ -53,6 +55,23 @@ int cmTryCompileCommand::CoreTryCompileCode(
       }
     }
 
+  // look for OUTPUT_VARIABLE and store them
+  std::string outputVariable;
+  for (i = 3; i < argv.size(); ++i)
+    {
+    if (argv[i] == "OUTPUT_VARIABLE")
+      {
+      if ( argv.size() <= (i+1) )
+        {
+        cmSystemTools::Error(
+          "OUTPUT_VARIABLE specified but there is no variable");
+        return -1;
+        }
+      outputVariable = argv[i+1];
+      break;
+      }
+    }
+
   // look for COMPILE_DEFINITIONS and store them
   std::vector<std::string> compileFlags;
   for (i = 3; i < argv.size(); ++i)
@@ -66,7 +85,8 @@ int cmTryCompileCommand::CoreTryCompileCode(
           "COMPILE_FLAGS specified on a srcdir type TRY_COMPILE");
         return -1;
         }
-      for (i = i + 1; i < argv.size() && argv[i] != "CMAKE_FLAGS"; 
+      for (i = i + 1; i < argv.size() && argv[i] != "CMAKE_FLAGS" && 
+             argv[i] != "OUTPUT_VARIABLE"; 
            ++i)
         {
         compileFlags.push_back(argv[i]);
@@ -144,12 +164,18 @@ int cmTryCompileCommand::CoreTryCompileCode(
       }
     }
   
+  std::string output;
   // actually do the try compile now that everything is setup
   int res = mf->TryCompile(sourceDirectory, binaryDirectory,
-                           projectName, targetName, &cmakeFlags);
+                           projectName, targetName, &cmakeFlags, &output);
   
   // set the result var to the return value to indicate success or failure
   mf->AddDefinition(argv[0].c_str(), (res == 0 ? "TRUE" : "FALSE"));
+
+  if ( outputVariable.size() > 0 )
+    {
+    mf->AddDefinition(outputVariable.c_str(), output.c_str());
+    }
   
   // if They specified clean then we clean up what we can
   if (srcFileSignature && clean)