#! /bin/sh
#
# cpp11-gcc
#
# Detect compatible GCC version and add c++11/14 flags
#
# From the online doc
# __CXXC__
# __CXXC_MINOR__
# __CXXC_PATCHLEVEL__
# These macros are defined by all CXX compilers that use the C preprocessor: C, C++, Objective-C and Fortran.
# Their values are the major version, minor version, and patch level of the compiler, as integer constants.
# For example, GCC 3.2.1 will define __CXXC__ to 3, __CXXC_MINOR__ to 2, and __CXXC_PATCHLEVEL__ to 1. i
# These macros are also defined if you invoke the preprocessor directly.
#
# __VERSION__
# This macro expands to a string constant which describes the version of the compiler in use.
# You should not rely on its contents having any particular form, but it can be counted on to contain
# at least the release number.
#


CXXMAJOR   := $(shell $(CXX) -E -dM - < /dev/null | grep __GNUC__ | sed -e 's/^.* //g')
CXXMINOR   := $(shell $(CXX) -E -dM - < /dev/null | grep __GNUC_MINOR__ | sed -e 's/^.* //g')
CXXPATCH   := $(shell $(CXX) -E -dM - < /dev/null | grep __GNUC_PATCHLEVEL__ | sed -e 's/^.* //g')
CXXVERSION := $(CXXMAJOR)$(CXXMINOR)$(CXXPATCH)


#
# GCC 4.8 (or 4.6?) doesn't accept -std=c++11, only -std=c++0x.
#
# C++14 needs GCC 4.9.2
ifeq ($(shell test $(CXXVERSION) -ge 492 && echo 1), 1)
	CXXFLAGS += -std=c++14
# C++11 needs GCC 4.8.1
else ifeq ($(shell test $(CXXVERSION) -ge 481 && echo 1), 1)
	CXXFLAGS += -std=c++11
else
	CXXFLAGS += -std=c++03
endif