conan/tools/build/flags.py
from conan.tools._compilers import cppstd_flag as cppstd_flag_settings
def cppstd_flag(conanfile):
"""
Returns flags specific to the C++ standard based on the ``conanfile.settings.compiler``,
``conanfile.settings.compiler.version`` and ``conanfile.settings.compiler.cppstd``.
It also considers when using GNU extension in ``settings.compiler.cppstd``, reflecting it in the
compiler flag. Currently, it supports GCC, Clang, AppleClang, MSVC, Intel, MCST-LCC.
In case there is no ``settings.compiler`` or ``settings.cppstd`` in the profile, the result will
be an **empty string**.
:param conanfile: The current recipe object. Always use ``self``.
:return: ``str`` with the standard C++ flag used by the compiler. e.g. "-std=c++11", "/std:c++latest"
"""
settings = conanfile.settings
return cppstd_flag_settings(settings)