Add GNUC -Wconversion, -Wsign-conversion warnings

Author: martinmoene

include/nonstd/string_view.hpp

@@ -68,7 +68,7 @@
 #define nssv_CPP17_OR_GREATER  (__cplusplus >= 201703L || nssv_MSVC_LANG >= 201703L )
 #define nssv_CPP20_OR_GREATER  (__cplusplus >= 202000L || nssv_MSVC_LANG >= 202000L )
 
-// use C++17 std::string_view if available:
+// use C++17 std::string_view if available and requested:
 
 #if defined(__has_include)
 # define nssv_HAS_INCLUDE( arg )  __has_include( arg )

test/CMakeLists.txt

@@ -65,7 +65,7 @@ elseif( CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang" )
     set( HAS_STD_FLAGS  TRUE )
     set( HAS_CPP98_FLAG TRUE )
 
-    set( OPTIONS     -Wall -Wno-missing-braces -Wno-unnamed-type-template-args -fno-elide-constructors )
+    set( OPTIONS     -Wall -Wextra -Wconversion -Wsign-conversion -Wno-missing-braces -Wno-unnamed-type-template-args -fno-elide-constructors )
     set( DEFINITIONS ${DEFCMN} )
 
     # GNU: available -std flags depends on version

test/tg.bat

@@ -1,6 +1,6 @@
 @setlocal
 @set std=%1
 @if "%std%"=="" set std=c++11
-g++ -std=%std% -O2 -Wall -Wextra -Wno-unused-parameter -Dnssv_CONFIG_STD_SV_OPERATOR=1 -Dnssv_CONFIG_USR_SV_OPERATOR=1 -Dnssv_STRING_VIEW_HEADER=\"string_view.hpp\" -I../include/nonstd -o string-view-lite.t.exe string-view-lite.t.cpp string-view.t.cpp && string-view-lite.t.exe
+g++ -std=%std% -O2 -Wall -Wextra -Wpedantic -Wconversion -Wsign-conversion -Wno-unused-parameter -Dnssv_CONFIG_STD_SV_OPERATOR=1 -Dnssv_CONFIG_USR_SV_OPERATOR=1 -Dnssv_STRING_VIEW_HEADER=\"string_view.hpp\" -I../include/nonstd -o string-view-lite.t.exe string-view-lite.t.cpp string-view.t.cpp && string-view-lite.t.exe
 @endlocal