@node ax_cxx_compile_stdcxx
@unnumberedsec ax_cxx_compile_stdcxx

@majorheading Synopsis

@smallexample
AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional])
@end smallexample

@majorheading Description

Check for baseline language coverage in the compiler for the specified
version of the C++ standard.  If necessary, add switches to CXX and
CXXCPP to enable support.  VERSION may be '11', '14', '17', or '20' for
the respective C++ standard version.

The second argument, if specified, indicates whether you insist on an
extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
-std=c++11).  If neither is specified, you get whatever works, with
preference for no added switch, and then for an extended mode.

The third argument, if specified 'mandatory' or if left unspecified,
indicates that baseline support for the specified C++ standard is
required and that the macro should error out if no mode with that
support is found.  If specified 'optional', then configuration proceeds
regardless, after defining HAVE_CXX$@{VERSION@} if and only if a
supporting mode is found.

@majorheading Source Code

Download the
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_cxx_compile_stdcxx.m4,latest
version of @file{ax_cxx_compile_stdcxx.m4}} or browse
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=history;f=m4/ax_cxx_compile_stdcxx.m4,the
macro's revision history}.

@majorheading License

@w{Copyright @copyright{} 2008 Benjamin Kosnik @email{bkoz@@redhat.com}} @* @w{Copyright @copyright{} 2012 Zack Weinberg @email{zackw@@panix.com}} @* @w{Copyright @copyright{} 2013 Roy Stogner @email{roystgnr@@ices.utexas.edu}} @* @w{Copyright @copyright{} 2014, 2015 Google Inc.; contributed by Alexey Sokolov @email{sokolov@@google.com}} @* @w{Copyright @copyright{} 2015 Paul Norman @email{penorman@@mac.com}} @* @w{Copyright @copyright{} 2015 Moritz Klammler @email{moritz@@klammler.eu}} @* @w{Copyright @copyright{} 2016, 2018 Krzesimir Nowak @email{qdlacz@@gmail.com}} @* @w{Copyright @copyright{} 2019 Enji Cooper @email{yaneurabeya@@gmail.com}} @* @w{Copyright @copyright{} 2020 Jason Merrill @email{jason@@redhat.com}} @* @w{Copyright @copyright{} 2021 Jörn Heusipp @email{osmanx@@problemloesungsmaschine.de}}

Copying and distribution of this file, with or without modification, are
permitted in any medium without royalty provided the copyright notice
and this notice are preserved.  This file is offered as-is, without any
warranty.