STYLE: fix documentation for command

Source/cmTryCompileCommand.h

@@ -77,30 +77,41 @@ public:
       "  TRY_COMPILE(RESULT_VAR bindir srcdir\n"
       "              projectName <targetname> <CMAKE_FLAGS <Flags>>\n"
       "              <OUTPUT_VARIABLE var>)\n"
-      "Try compiling a program.  Return the success or failure in "
-      "RESULT_VAR. If <target name> is specified then build just that target "
+      "Try compiling a program.  In this form, srcdir should contain a complete "
+      "CMake project with a CMakeLists.txt file and all sources. The bindir and "
+      "srcdir will not be deleted after this command is run. "
+      "If <target name> is specified then build just that target "
       "otherwise the all or ALL_BUILD target is built.\n"
       "  TRY_COMPILE(RESULT_VAR bindir srcfile\n"
       "              <CMAKE_FLAGS <Flags>>\n"
       "              <COMPILE_DEFINITIONS <flags> ...>\n"
       "              <OUTPUT_VARIABLE var>)\n"
-      "Try compiling a srcfile.  Return the success or failure in "
-      "RESULT_VAR. CMAKE_FLAGS can be used to pass -DVAR:TYPE=VALUE flags "
-      "to cmake.  Some extra flags that can be included are,  "
+      "Try compiling a srcfile.  In this case, the user need only supply a "
+      "source file.  CMake will create the appropriate CMakeLists.txt file "
+      "to build the source. "
+      "In this version all files in bindir/CMakeFiles/CMakeTmp, "
+      "will be cleaned automatically, for debugging a --debug-trycompile can "
+      "be passed to cmake to avoid the clean. Some extra flags that "
+      " can be included are,  "
       "INCLUDE_DIRECTORIES, LINK_DIRECTORIES, and LINK_LIBRARIES.  "
       "COMPILE_DEFINITIONS are -Ddefinition that will be passed to the "
-      "compile line. If srcfile is specified the files in "
-      "bindir/CMakeFiles/CMakeTmp "
-      "are cleaned automatically. If OUTPUT_VARIABLE is specified, then the "
-      "output from the build process is stored in the given variable. "
+      "compile line.  "
+
       "TRY_COMPILE creates a CMakeList.txt "
-      "file on the fly, and in that file it looks like this:\n"
+      "file on the fly that looks like this:\n"
       "  ADD_DEFINITIONS( <expanded COMPILE_DEFINITIONS from calling "
       "cmake>)\n"
       "  INCLUDE_DIRECTORIES(${INCLUDE_DIRECTORIES})\n"
       "  LINK_DIRECTORIES(${LINK_DIRECTORIES})\n"
       "  ADD_EXECUTABLE(cmTryCompileExec sources)\n"
-      "  TARGET_LINK_LIBRARIES(cmTryCompileExec ${LINK_LIBRARIES})\n";
+      "  TARGET_LINK_LIBRARIES(cmTryCompileExec ${LINK_LIBRARIES})\n"
+      "In both versions of the command, "
+      "if OUTPUT_VARIABLE is specified, then the "
+      "output from the build process is stored in the given variable. "
+      "Return the success or failure in "
+      "RESULT_VAR. CMAKE_FLAGS can be used to pass -DVAR:TYPE=VALUE flags "
+      "to the cmake that is run during the build. "
+      "";
     }
   
   cmTypeMacro(cmTryCompileCommand, cmCommand);