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.Dd October 14, 2012
.Dt COMPILERS.CONF 5
.Os
.Sh NAME
.Nm compilers.conf
.Nd configuration file for external compilers
.Sh SYNOPSIS
.Pa /etc/compilers.conf
.Sh DESCRIPTION
The
.Nm
file allows to configure
.Dq external
compilers for usage with the
.Dx
.Xr build 7
system.
.Pp
The
.Pa /etc/defaults/compilers.conf
file specifies the default settings for all variables, the
.Pa /etc/compilers.conf
file specifies override settings.
.Pp
The following variables are available:
.Bl -tag -width ".Va <version>_CPPFLAGS"
.It Va <version>_CC
The pathname of the
.Nm cc
program of the compiler.
.It Va <version>_CFLAGS
Any additional flags to pass to
.Va <version>_CC .
.It Va <version>_CPP
The pathname of the
.Nm cpp
program of the compiler.
.It Va <version>_CPPFLAGS
Any additional flags to pass to
.Va <version>_CPP .
.It Va <version>_CXX
The pathname of the
.Nm c++
program of the compiler.
.It Va <version>_CXXFLAGS
Any additional flags to pass to
.Va <version>_CXX .
.El
.Pp
Currently, defaults are provided for
.Nm clang
(installed from
.Xr pkgsrc 7 Ap s
.Pa lang/clang ) ,
.Nm clangsvn
(installed from SVN trunk as described in
.Pa http://clang.llvm.org/get_started.html ) ,
.Nm gcc46
(installed from
.Xr pkgsrc 7 Ap s
.Pa lang/gnat-aux ) ,
and
.Nm pcc
(installed from
.Xr pkgsrc 7 Ap s
.Pa lang/pcc-current ) .
.Sh IMPLEMENTATION NOTES
In
.Dx ,
compilers are selected by setting the
.Ev CCVER
variable.
The
.Pa cpp ,
.Pa cc ,
etc\&. programs in
.Pa /usr/bin
are actually links to the
.Xr objformat 1
deflector program which is responsible for executing the
correct programs (located in
.Pa /usr/libexec/$CCVER ) .
.Pp
Traditionally,
.Dx
has 2 compilers in base, one of which is the default compiler and the other
is either a newer or older version.
In order to allow additional non-base compilers into
.Dx Ap s
build process,
.Xr objformat 1
deflects to
.Pa /usr/libexec/custom
when
.Ev CCVER Ap s
setting is not one of the compilers in base.
This directory contains a
.Pa cc
wrapper script (and some links to it).
The wrapper script then takes care of making the compiler look and behave
like a compiler in base.
.Pp
The settings in
.Nm
specify paths and flags for the
.Pa /usr/libexec/custom/cc
script.
.Sh FILES
.Bl -tag -width ".Pa /etc/compilers.conf" -compact
.It Pa /etc/compilers.conf
external compiler configuration file
.El
.Sh EXAMPLES
Once configured the compiler can be used like this:
.Bd -literal -offset indent
env CCVER=clang make
.Ed
.Pp
To try building world and kernel, use:
.Bd -literal -offset indent
cd /usr/src
env WORLD_CCVER=<version> make -DNO_GCC47 buildworld
env WORLD_CCVER=<version> make buildkernel KERNCONF=MYCONF
.Ed
.Sh SEE ALSO
.Xr objformat 1 ,
.Xr build 7
.Sh HISTORY
The
.Nm
file first appeared in
.Dx 2.3 .