diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 7215e766e6..8b1f0baf55 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -1102,7 +1102,7 @@ cmMakefile::UpdateOutputToSourceMap(std::string const& output,
 
 //----------------------------------------------------------------------------
 cmSourceFile*
-cmMakefile::AddCustomCommandToOutput(const char* output,
+cmMakefile::AddCustomCommandToOutput(const std::string& output,
                                      const std::vector<std::string>& depends,
                                      const char* main_dependency,
                                      const cmCustomCommandLines& commandLines,
diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index aa25f09956..e165fd8dfd 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -183,7 +183,7 @@ public:
     bool replace = false,
     bool escapeOldStyle = true);
   cmSourceFile* AddCustomCommandToOutput(
-    const char* output,
+    const std::string& output,
     const std::vector<std::string>& depends,
     const char* main_dependency,
     const cmCustomCommandLines& commandLines,