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package Alien::OpenMP;

use parent 'Alien::Base';
use Config ();
use Alien::OpenMP::configure ();

our $VERSION = '0.003006';

# "public" Alien::Base method implementations

# we can reuse cflags for gcc/gomp; hopefully this will
# remain the case for all supported compilers
sub lddlflags { shift->libs }

# Inline related methods

sub Inline {
  my ($self, $lang) = @_;
  my $params = $self->SUPER::Inline($lang);
  $params->{CCFLAGSEX} = delete $params->{INC};
  return {
    %$params,
    LDDLFLAGS     => join( q{ }, $Config::Config{lddlflags}, $self->lddlflags() ),
    AUTO_INCLUDE  => $self->runtime_prop->{auto_include},
  };
}

1;

__END__

=head1 NAME

Alien::OpenMP - Encapsulate system info for OpenMP

=head1 SYNOPSIS

    use Alien::OpenMP;
    say Alien::OpenMP->cflags;       # e.g. '-fopenmp' if gcc
    say Alien::OpenMP->lddlflags;    # e.g. '-fopenmp' if gcc
    say Alien::OpenMP->auto_include; # e.g. '#include <omp.h>' if gcc

=head1 DESCRIPTION

This module encapsulates the knowledge required to compile OpenMP programs
C<$Config{ccname}>. C<C>, C<Fortran>, and C<C++> programs annotated
with declarative OpenMP pragmas will still compile if the compiler (and
linker if this is a separate process) is not passed the appropriate flag
to enable OpenMP support. This is because all pragmas are hidden behind
full line comments (with the addition of OpenMP specific C<sentinels>,
as they are called).

All compilers require OpenMP to be explicitly activated during compilation;
for example, GCC's implementation, C<GOMP>, is invoked by the C<-fopenmp>
flag.

Most major compilers support OpenMP, including: GCC, Intel, IBM,
Portland Group, NAG, and those compilers created using LLVM. GCC's OpenMP
implementation, C<GOMP>, is available in all modern versions. Unfortunately,
while OpenMP is a well supported standard; compilers are not required to
use the same commandline switch to activate support. All compilers that
support OpenMP use slightly different ways of invoking it.

=head2 Compilers Supported by this module

At this time, the following compilers are supported:

=over 4

=item C<gcc>

C<-fopenmp> enables OpenMP support in via compiler and linker:

    gcc -fopenmp ./my-openmp.c -o my-openmp.x

=item C<clang> EXPERIMENTAL

C<-fopenmp> enables OpenMP support via compiler and linker in recent
versions of C<clang>. MacOS shipped versions are missing the library
which needs installing either with L<Homebrew|https://brew.sh> or
L<Macports|https://www.macports.org>.

=back

=head2 Note On Compiler Support

If used for an unsupported compiler, C<ExtUtils::MakeMaker::os_unsupported>
is invoked, which results an exception propagating from this method being
raised with the value of C<qq{OS unsupported\n}> (note the new line).

This module assumes that the compiler in question is the same one used to
build C<perl>. Since the vast majority of C<perl>s are building using
C<gcc>, initial support is targeting it. However, like C<perl>, many
other compilers may be used.

Adding support for a new compiler should be straightforward; please
section on contributing, below.

=head2 Contributing

The biggest need is to support additional compilers. OpenMP is a well