cmake: Provide guidance when an invalid -G option is given

Print a list of generators if no generator or an invalid one is
supplied.

Signed-off-by: Gerald Combs <gerald@wireshark.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/Source/cmDocumentation.cxx b/Source/cmDocumentation.cxx
index 8c17536..4f34755 100644
--- a/Source/cmDocumentation.cxx
+++ b/Source/cmDocumentation.cxx
@@ -138,6 +138,8 @@ bool cmDocumentation::PrintDocumentation(Type ht, std::ostream& os)
       return this->PrintHelpListVariables(os);
     case cmDocumentation::ListPolicies:
       return this->PrintHelpListPolicies(os);
+    case cmDocumentation::ListGenerators:
+      return this->PrintHelpListGenerators(os);
     case cmDocumentation::Version:
       return this->PrintVersion(os);
     case cmDocumentation::OldCustomModules:
@@ -817,6 +819,19 @@ bool cmDocumentation::PrintHelpListPolicies(std::ostream& os)
 }
 
 //----------------------------------------------------------------------------
+bool cmDocumentation::PrintHelpListGenerators(std::ostream& os)
+{
+  std::map<std::string,cmDocumentationSection*>::iterator si;
+  si = this->AllSections.find("Generators");
+  if(si != this->AllSections.end())
+    {
+    this->Formatter.SetIndent("  ");
+    this->Formatter.PrintSection(os, *si->second);
+    }
+  return true;
+}
+
+//----------------------------------------------------------------------------
 bool cmDocumentation::PrintHelpOneVariable(std::ostream& os)
 {
   std::string vname = cmSystemTools::HelpFileName(this->CurrentArgument);