# dpkg manual page - dpkg-buildpackage(1)
#
# Copyright © 1995-1996 Ian Jackson
# Copyright © 2000 Wichert Akkerman <wakkerma@debian.org>
# Copyright © 2007-2008 Frank Lichtenheld <djpig@debian.org>
# Copyright © 2008-2015 Guillem Jover <guillem@debian.org>
# Copyright © 2008-2012 Raphaël Hertzog <hertzog@debian.org>
#
# This is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

=encoding utf8

=head1 NAME

dpkg-buildpackage - build binary or source packages from sources

=head1 SYNOPSIS

B<dpkg-buildpackage> [I<option>...] [B<-->] [I<filename>.dsc|I<directory>]

=head1 DESCRIPTION

B<dpkg-buildpackage>
is a program that automates the process of building a Debian package.

The I<filename>.dsc and I<directory> arguments are supported since dpkg 1.22.7.
Their semantics are experimental.

It
consists of the following steps:

=over

=item B<1.>

It runs the B<preinit> hook before reading any source file.
If a B<.dsc> file has been specified it unpacks it anew and
changes directory to it,
if a I<directory> has been specified it changes directory to it,
otherwise it expects the current directory to contain the source tree.
It prepares the build environment by setting various environment
variables (see B<ENVIRONMENT>), runs the B<init> hook, and calls
B<dpkg-source --before-build> (unless B<-T> or B<--target>
has been used).

=item B<2.>

It checks that the build-dependencies and build-conflicts
are satisfied (unless B<-d> or B<--no-check-builddeps> is specified).

=item B<3.>

If one or more specific targets have been selected with the B<-T> or
B<--target> option, it calls those targets and stops here.
Otherwise it
runs the B<preclean> hook and calls B<fakeroot debian/rules clean> to
clean the build-tree (unless B<-nc> or B<--no-pre-clean>
is specified).

=item B<4.>

It runs the B<source> hook and calls B<dpkg-source -b> to generate
the source package (if a B<source> build has been requested with
B<--build> or equivalent options,
and if no B<.dsc> has been specified).

=item B<5.>

It runs the B<build> hook and calls B<debian/rules> I<build-target>,
then runs the B<binary> hook followed by B<fakeroot debian/rules>
I<binary-target> (unless a source-only build has been requested with
B<--build=source> or equivalent options).
Note that I<build-target> and I<binary-target> are either B<build>
and B<binary> (default case, or if an B<any> and B<all> build
has been requested with B<--build> or equivalent options), or
B<build-arch> and B<binary-arch> (if an B<any> and not B<all>
build has been requested with B<--build> or equivalent options), or
B<build-indep> and B<binary-indep> (if an B<all> and not B<any>
build has been requested with B<--build> or equivalent options).

=item B<6.>

It runs the B<buildinfo>
hook and calls B<dpkg-genbuildinfo> to generate a B<.buildinfo> file.
Several B<dpkg-buildpackage> options are forwarded to
B<dpkg-genbuildinfo>.
If a I<.dsc> has been specified,
then it will be referenced in the generated B<.buildinfo> file,
as we can ascertain the provenance of the source tree.

=item B<7.>

It runs the B<changes> hook and calls B<dpkg-genchanges> to
generate a B<.changes> file.
The name of the B<.changes> file will depend on the type of build and
will be as specific as necessary but not more; the name will be:

=over

=item I<source-name>B<_>I<binary-version>B<_>I<arch>B<.changes>

for a build that includes B<any>

=item I<source-name>B<_>I<binary-version>B<_>B<all.changes>

otherwise for a build that includes B<all>

=item I<source-name>B<_>I<source-version>B<_>B<source.changes>.

otherwise for a build that includes B<source>

=back

Many B<dpkg-buildpackage> options are forwarded to
B<dpkg-genchanges>.

=item B<8.>

It runs the B<postclean> hook and if B<-tc> or B<--post-clean>
is specified, it will call B<fakeroot debian/rules clean> again.

=item B<9.>

It calls B<dpkg-source --after-build>.

=item B<10.>

It runs the B<check> hook and calls a package checker for the
B<.changes> file (if a command is specified in B<DEB_CHECK_COMMAND> or
with B<--check-command>).

=item B<11.>

It runs the B<sign> hook and signs using the OpenPGP backend (as long as it
is not an UNRELEASED build, or B<--no-sign> is specified) to sign the
B<.dsc> file (if any, unless
B<-us> or B<--unsigned-source> is specified), the B<.buildinfo>
file (unless B<-ui>, B<--unsigned-buildinfo>,
B<-uc> or B<--unsigned-changes> is specified) and
the B<.changes> file (unless B<-uc> or B<--unsigned-changes>
is specified).

=item B<12.>

If a B<.dsc> file has been specified,
it removes the extracted source directory.

=item B<13.>

It runs the B<done> hook.

=back

=head1 OPTIONS

All long options can be specified both on the command line and in the
B<dpkg-buildpackage> system and user configuration files.
Each line in the configuration file is either an option (exactly the same
as the command line option but without leading hyphens) or a comment (if
it starts with a ‘B<#>’).

=over

=item B<--build=>I<type>

Specifies the build I<type> from a comma-separated list of components
(since dpkg 1.18.5).
All the specified components get combined to select the single build type
to use, which implies a single build run with a single F<.changes> file
generated.
Passed to B<dpkg-genchanges>.

The allowed values are:

=over

=item B<source>

Builds the source package.

B<Note>: When using this value standalone and if what you want is simply to
(re-)build the source package from a clean source tree, using
B<dpkg-source> directly is always a better option as it does not
require any build dependencies to be installed which are otherwise
needed to be able to call the B<clean> target.

=item B<any>

Builds the architecture specific binary packages.

=item B<all>

Builds the architecture independent binary packages.

=item B<binary>

Builds the architecture specific and independent binary packages.
This is an alias for B<any,all>.

=item B<full>

Builds everything.
This is an alias for B<source,any,all>, and the same as the default
case when no build option is specified.

=back

=item B<-g>

Equivalent to B<--build=source,all> (since dpkg 1.17.11).

=item B<-G>

Equivalent to B<--build=source,any> (since dpkg 1.17.11).

=item B<-b>

Equivalent to B<--build=binary> or B<--build=any,all>.

=item B<-B>

Equivalent to B<--build=any>.

=item B<-A>

Equivalent to B<--build=all>.

=item B<-S>

Equivalent to B<--build=source>.

=item B<-F>

Equivalent to B<--build=full>, B<--build=source,binary> or
B<--build=source,any,all> (since dpkg 1.15.8).

=item B<--target=>I<target>[,...]

=item B<--target> I<target>[,...]

=item B<-T>, B<--rules-target=>I<target>[,...]

Calls B<debian/rules> I<target> once per target specified, after
having setup the build environment (except for calling
B<dpkg-source --before-build>), and stops the package build process
here (since dpkg 1.15.0, long option since dpkg 1.18.8, multi-target
support since dpkg 1.18.16).
If B<--as-root> is also given, then the command is executed
as root (see B<--root-command>).
Note that known targets that are required to
be run as root do not need this option (i.e. the B<clean>, B<binary>,
B<binary-arch> and B<binary-indep> targets).

=item B<--as-root>

Only meaningful together with B<--target> (since dpkg 1.15.0).
Requires that the target be run with root rights.

=item B<-si>

=item B<-sa>

=item B<-sd>

=item B<-v>I<version>

=item B<-C>I<changes-description>

=item B<-m>I<maintainer-address>

=item B<-e>I<maintainer-address>

Passed unchanged to B<dpkg-genchanges>.
See its manual page.

=item B<--build-by=>I<maintainer-address>

=item B<--source-by=>I<maintainer-address> (since dpkg 1.21.10)

Pass as B<-m> to B<dpkg-genchanges>.
See its manual page.

=item B<--release-by=>I<maintainer-address>

=item B<--changed-by=>I<maintainer-address> (since dpkg 1.21.10)

Pass as B<-e> to B<dpkg-genchanges>.
See its manual page.

=item B<-a>, B<--host-arch> I<architecture>

Specify the Debian architecture we build for (long option since dpkg 1.17.17).
The architecture of the
machine we build on is determined automatically, and is also the default
for the host machine.

=item B<-t>, B<--host-type> I<gnu-system-type>

Specify the GNU system type we build for (long option since dpkg 1.17.17).
It can be used in place
of B<--host-arch> or as a complement to override the default GNU system type
of the host Debian architecture.

=item B<--target-arch> I<architecture>

Specify the Debian architecture the binaries built will build for
(since dpkg 1.17.17).
The default value is the host machine.

=item B<--target-type> I<gnu-system-type>

Specify the GNU system type the binaries built will build for
(since dpkg 1.17.17).
It can be
used in place of B<--target-arch> or as a complement to override the
default GNU system type of the target Debian architecture.

=item B<-P>, B<--build-profiles=>I<profile>[B<,>...]

Specify the profile(s) we build, as a comma-separated list (since dpkg 1.17.2,
long option since dpkg 1.18.8).
The default
behavior is to build for no specific profile.
Also sets them (as a space
separated list) as the B<DEB_BUILD_PROFILES> environment variable which
allows, for example, B<debian/rules> files to use this information for
conditional builds.

=item B<-j>, B<--jobs>[=I<jobs>|B<auto>]

Specifies the number of jobs allowed to be run simultaneously
(since dpkg 1.14.7, long option since dpkg 1.18.8).
The number of jobs matching the number of online processors if B<auto> is
specified (since dpkg 1.17.10), or unlimited number if I<jobs> is not
specified.
The default behavior is B<auto> (since dpkg 1.18.11) in non-forced mode
(since dpkg 1.21.10), and as such it is always safer to use with any
package including those that are not parallel-build safe.
Setting the number of jobs to B<1> will restore serial execution.

Will add B<parallel=>I<jobs> or B<parallel> to the B<DEB_BUILD_OPTIONS>
environment variable which allows debian/rules files to opt-in to use this
information for their own purposes.
The I<jobs> value will override the B<parallel=>I<jobs> or
B<parallel> option in the B<DEB_BUILD_OPTIONS> environment variable.
Note that the B<auto> value will get replaced by the actual number of
currently active processors, and as such will not get propagated to any
child process.
If the number of online processors cannot be inferred then
the code will fallback to using serial execution (since dpkg 1.18.15),
although this should only happen on exotic and unsupported systems.

=item B<-J>, B<--jobs-try>[=I<jobs>|B<auto>]

This option (since dpkg 1.18.2, long option since dpkg 1.18.8) is equivalent
to the B<-j> above.

Since the behavior for B<-j> changed in dpkg 1.21.10 to the opt-in mode,
you can use this option instead if you need to guarantee semantics across
dpkg release series.

=item B<--jobs-force>[=I<jobs>|B<auto>]

This option (since dpkg 1.21.10) is equivalent to the B<--jobs> option
except that it will enable forced parallel mode, by adding the B<make> B<-j>
option with the computed number of parallel jobs to the B<MAKEFLAGS>
environment variable.

This should cause all subsequent make invocations to inherit the option,
thus forcing the parallel setting on the packaging (and possibly the
upstream build system if that uses L<make(1)>) regardless of their support
for parallel builds, which might cause build failures.

B<Note>: Any Makefile that is not parallel-safe should be considered to be buggy.
These should either be made parallel-safe, or marked as not being safe with
the L<make(1)> B<.NOTPARALLEL> target.

=item B<-D>, B<--check-builddeps>

Check build dependencies and conflicts; abort if unsatisfied (long option
since dpkg 1.18.8).
This is the default behavior.

=item B<-d>, B<--no-check-builddeps>

Do not check build dependencies and conflicts (long option since dpkg 1.18.8).

=item B<--ignore-builtin-builddeps>

Do not check built-in build dependencies and conflicts (since dpkg 1.18.2).
These are the distribution specific implicit build dependencies usually
required in a build environment, the so called Build-Essential package set.

=item B<--rules-requires-root>

Do not honor the B<Rules-Requires-Root> field,
falling back to its legacy default value B<binary-targets> (since dpkg 1.19.1).

=item B<-nc>, B<--no-pre-clean>

Do not clean the source tree before building (long option since dpkg 1.18.8).
Implies B<-b> if nothing else has been selected among B<-F>,
B<-g>, B<-G>, B<-B>, B<-A> or B<-S>.
Implies B<-d> with B<-S> (since dpkg 1.18.0).

=item B<--pre-clean>

Clean the source tree before building (since dpkg 1.18.8).
This is the default behavior.

=item B<-tc>, B<--post-clean>

Clean the source tree (using
I<gain-root-command>
B<debian/rules clean>)
after the package has been built (long option since dpkg 1.18.8).

=item B<--no-post-clean>

Do not clean the source tree after the package has been built
(since dpkg 1.19.1).
This is the default behavior.

=item B<--sanitize-env>

Sanitize the build environment (since dpkg 1.20.0).
This will reset or remove environment variables, umask, and any other process
attributes that might otherwise adversely affect the build of packages.
Because the official entry point to build packages is B<debian/rules>,
packages cannot rely on these settings being in place, and thus should work
even when they are not.
What to sanitize is vendor specific.

=item B<-r>, B<--root-command=>I<gain-root-command>

When
B<dpkg-buildpackage>
needs to execute part of the build process as root, it prefixes the
command it executes with
I<gain-root-command>
if one has been specified (long option since dpkg 1.18.8).
Otherwise, if none has been specified,
B<fakeroot> will be used by default, if the command is present.
I<gain-root-command>
should start with the name of a program on the
B<PATH>
and will get as arguments the name of the real command to run and the
arguments it should take.
I<gain-root-command>
can include parameters (they must be space-separated) but no shell
metacharacters.
I<gain-root-command>
might typically be
B<fakeroot>, B<sudo>, B<super> or B<really>.
B<su>
is not suitable, since it can only invoke the user's shell with
B<-c>
instead of passing arguments individually to the command to be run.

=item B<-R>, B<--rules-file=>I<rules-file>

Building a Debian package usually involves invoking
B<debian/rules>
as a command with several standard parameters (since dpkg 1.14.17,
long option since dpkg 1.18.8).
With this option it's
possible to use another program invocation to build the package (it can
include space separated parameters).
Alternatively it can be used to execute the standard rules file with
another make program (for example by using
B</usr/local/bin/make -f debian/rules>
as I<rules-file>).

=item B<--check-command=>I<check-command>

Command used to check the B<.changes> file itself and any artifact built
referenced in the file (since dpkg 1.17.6).
The command should take the B<.changes> pathname
as an argument.
This command will usually be B<lintian>.

=item B<--check-option=>I<opt>

Pass option I<opt> to the I<check-command> specified with
B<DEB_CHECK_COMMAND> or B<--check-command> (since dpkg 1.17.6).
Can be used multiple times.

=item B<--hook->I<hook-name>B<=>I<hook-command>

Set the specified shell code I<hook-command> as the hook I<hook-name>,
which will run at the times specified in the run steps (since dpkg 1.17.6).
The hooks will
always be executed even if the following action is not performed (except
for the B<binary> hook).
All the hooks will run in the unpacked source directory.

Some hooks can receive addition information through environment variables
(since dpkg 1.22.0).
All hooks get the hook name in the B<DPKG_BUILDPACKAGE_HOOK_NAME> environment
variable (since dpkg 1.22.0).

B<Note>: Hooks can affect the build process, and cause build failures if
their commands fail, so watch out for unintended consequences.

The current I<hook-name> supported are:

=over

=item B<preinit>

=item B<init>

=item B<preclean>

=item B<source>

Gets B<DPKG_BUILDPACKAGE_HOOK_SOURCE_OPTIONS> with the space-separated lists
of options that will passed to the B<dpkg-source> call.

=item B<build>

Gets B<DPKG_BUILDPACKAGE_HOOK_BUILD_TARGET> with the name of the
B<debian/rules> build target called.
Before dpkg 1.22.7 the variable was only set if the target was called.

=item B<binary>

Gets B<DPKG_BUILDPACKAGE_HOOK_BINARY_TARGET> with the name of the
B<debian/rules> binary target called, but only if called.

=item B<buildinfo>

Gets B<DPKG_BUILDPACKAGE_HOOK_BUILDINFO_OPTIONS> with the space-separated lists
of options that will passed to the B<dpkg-genbuildinfo> call.

=item B<changes>

Gets B<DPKG_BUILDPACKAGE_HOOK_CHANGES_OPTIONS> with the space-separated lists
of options that will passed to the B<dpkg-genchanges> call.

=item B<postclean>

=item B<check>

Gets B<DPKG_BUILDPACKAGE_HOOK_CHECK_OPTIONS> with the space-separated lists
of options that will passed to the check command call.

=item B<sign>

=item B<done>

=back

The I<hook-command> supports the following substitution format string,
which will get applied to it before execution:

=over

=item B<%%>

A single % character.

=item B<%a>

A boolean value (0 or 1), representing whether the following action is
being performed.

=item B<%p>

The source package name.

=item B<%v>

The source package version.

=item B<%s>

The source package version (without the epoch).

=item B<%u>

The upstream version.

=back

=item B<--buildinfo-file=>I<filename>

Set the I<filename> for the generated B<.buildinfo> file (since dpkg 1.21.0).

=item B<--buildinfo-option=>I<opt>

Pass option I<opt> to B<dpkg-genbuildinfo> (since dpkg 1.18.11).
Can be used multiple times.

=item B<--sign-backend=>I<sign-backend>

Specify an OpenPGP backend interface to use when invoking the I<sign-command>
(since dpkg 1.21.10).

The default is B<auto>, where the best current backend available will be used.
The specific OpenPGP backends supported in order of preference are:

=over 4

=item B<sop>

Any conforming Stateless OpenPGP (SOP) implementation,
such as sqop, rsop, gosop or pgpainless-cli.

=item B<sq>

From Sequoia-PGP.

=item B<gpg>

From GnuPG.

=back

=item B<-p>, B<--sign-command=>I<sign-command>

When B<dpkg-buildpackage> needs to execute an OpenPGP backend command to
sign a source control (B<.dsc>) file, a B<.buildinfo> file or a B<.changes>
file it will run
I<sign-command> (searching the B<PATH> if necessary) instead of the
default or auto-detected backend command (long option since dpkg 1.18.8).
I<sign-command> will get all the backend specific arguments according to
the B<--sign-backend> selected.
I<sign-command> should not contain spaces or any other shell metacharacters.

=item B<-k>, B<--sign-keyid=>I<key-id>

=item B<--sign-key=>I<key-id>

Specify an OpenPGP key-ID (either a fingerprint or a user-ID) for the
secret key to use when signing packages (B<--sign-key> since dpkg 1.18.8,
B<--sign-keyid> since dpkg 1.21.10).

=item B<--sign-keyfile=>I<key-file>

Specify an OpenPGP I<key-file> containing the secret key to use when signing
packages (since dpkg 1.21.10).

B<Note>: For security reasons the I<key-file> is best kept locked with a
password.

=item B<-us>, B<--unsigned-source>

Do not sign the source package (long option since dpkg 1.18.8).

=item B<-ui>, B<--unsigned-buildinfo>

Do not sign the B<.buildinfo> file (since dpkg 1.18.19).

=item B<-uc>, B<--unsigned-changes>

Do not sign the B<.buildinfo> and B<.changes> files
(long option since dpkg 1.18.8).

=item B<--no-sign>

Do not sign any file, this includes the source package, the B<.buildinfo>
file and the B<.changes> file (since dpkg 1.18.20).

=item B<--force-sign>

Force the signing of the resulting files (since dpkg 1.17.0), regardless of
B<-us>, B<--unsigned-source>,
B<-ui>, B<--unsigned-buildinfo>,
B<-uc>, B<--unsigned-changes>
or other internal heuristics.

=item B<-sn>

=item B<-ss>

=item B<-sA>

=item B<-sk>

=item B<-su>

=item B<-sr>

=item B<-sK>

=item B<-sU>

=item B<-sR>

=item B<-i>, B<--diff-ignore>[=I<regex>]

=item B<-I>, B<--tar-ignore>[=I<pattern>]

=item B<-z>, B<--compression-level=>I<level>

=item B<-Z>, B<--compression=>I<compressor>

Passed unchanged to B<dpkg-source>.
See its manual page.

=item B<--source-option=>I<opt>

Pass option I<opt> to B<dpkg-source> (since dpkg 1.15.6).
Can be used multiple times.

=item B<--changes-file=>I<filename>

Set the I<filename> for the generated B<.changes> file (since dpkg 1.21.0).

=item B<--changes-option=>I<opt>

Pass option I<opt> to B<dpkg-genchanges> (since dpkg 1.15.6).
Can be used multiple times.

=item B<--admindir=>I<dir>

=item B<--admindir> I<dir>

Change the location of the B<dpkg> database (since dpkg 1.14.0).
The default location is I<%ADMINDIR%>.

=item B<-?>, B<--help>

Show the usage message and exit.

=item B<--version>

Show the version and exit.

=back

=head1 ENVIRONMENT

=head2 External environment

=over

=item B<DEB_CHECK_COMMAND>

If set, it will be used as the command to check the B<.changes> file
(since dpkg 1.17.6).
Overridden by the B<--check-command> option.

=item B<DEB_SIGN_KEYID>

If set, it will be used to sign the B<.changes>, B<.buildinfo> and B<.dsc>
files (since dpkg 1.17.2).
Overridden by the B<--sign-keyid> option.

=item B<DEB_SIGN_KEYFILE>

If set, it will be used to sign the B<.changes>, B<.buildinfo> and B<.dsc>
files (since dpkg 1.21.10).
Overridden by the B<--sign-keyfile> option.

=item B<DEB_BUILD_OPTIONS>

If set, it will contain a space-separated list of options that affect
the behavior of some dpkg tools involved in package building,
and might affect the package build process if the code in F<debian/rules>
honors them.
These options can have parameters specified immediately after an
equal sign (‘B<=>‘).
For options that support multiple parameters,
these will not be separated by spaces,
as these are reserved to separate options.

The following are the options known and supported by dpkg tools,
other options honored by F<debian/rules> might be defined by distribution
specific policies.

=over

=item B<parallel=>I<N>

The F<debian/rules> in the packaging might use this option to set up
the build process to use I<N> parallel jobs.
It is overridden by the B<--jobs> and B<--jobs-force> options.

=item B<nocheck>

B<dpkg-buildpackage> will ignore the B<DEB_CHECK_COMMAND> variable.
The F<debian/rules> in the packaging is not expected to run test suites
during the build.

=item B<noopt>

If F<debian/rules> calls B<dpkg-buildflags> to set up the build flags,
those will be set to not enable any optimizations.

=item B<nostrip>

The F<debian/rules> in the packaging should ensure that objects do not get
the debugging information stripped.
If F<debian/rules> includes the B<mk/buildtools.mk> make fragment the
B<STRIP> make variable will respect this option.

=item B<terse>

B<dpkg-buildpackage> will append the B<--no-print-directory> L<make(1)>
flag to the B<MAKEFLAGS> environment variable.
The F<debian/rules> in the packaging should reduce verbosity, while not
being completely quiet.

=item B<hardening=>I<feature-spec>

=item B<reproducible=>I<feature-spec>

=item B<abi=>I<feature-spec>

=item B<future=>I<feature-spec>

=item B<qa=>I<feature-spec>

=item B<optimize=>I<feature-spec>

=item B<sanitize=>I<feature-spec>

These are feature areas that control build flag features.
See L<dpkg-buildflags(1)> for further details.

=back

=item B<DEB_BUILD_PROFILES>

If set, it will be used as the active build profile(s) for the package
being built (since dpkg 1.17.2).
It is a space separated list of profile names.
Overridden by the B<-P> option.

=item B<DPKG_COLORS>

Sets the color mode (since dpkg 1.18.5).
The currently accepted values are: B<auto> (default), B<always> and
B<never>.

=item B<DPKG_NLS>

If set, it will be used to decide whether to activate Native Language Support,
also known as internationalization (or i18n) support (since dpkg 1.19.0).
The accepted values are: B<0> and B<1> (default).

=back

=head2 Internal environment

Even if B<dpkg-buildpackage> exports some variables, B<debian/rules>
should not rely on their presence and should instead use the
respective interface to retrieve the needed values, because that
file is the main entry point to build packages and running it
standalone should be supported.

=over

=item B<DEB_BUILD_*>

=item B<DEB_HOST_*>

=item B<DEB_TARGET_*>

B<dpkg-architecture> is called with the B<-a> and B<-t>
parameters forwarded.
Any variable that is output by its B<-s>
option is integrated in the build environment.

=item B<DEB_RULES_REQUIRES_ROOT>

This variable is set to the value obtained from the B<Rules-Requires-Root>
field, the dpkg-build-api level or from the command-line.
When set, it will be a valid value for the B<Rules-Requires-Root> field.
It is used to notify B<debian/rules> whether the B<rootless-builds.txt>
specification is supported.

=item B<DEB_GAIN_ROOT_CMD>

This variable is set to I<gain-root-command> when the field
B<Rules-Requires-Root> is set to a value different to B<no> and
B<binary-targets>.

=item B<SOURCE_DATE_EPOCH>

This variable is set to the Unix timestamp since the epoch of the
latest entry in I<debian/changelog>, if it is not already defined.

=back

=head1 FILES

=over

=item I<%PKGCONFDIR%/buildpackage.conf>

System wide configuration file

=item I<$XDG_CONFIG_HOME/dpkg/buildpackage.conf> or

=item I<$HOME/.config/dpkg/buildpackage.conf>

User configuration file.

=back

=head1 NOTES

=head2 Compiler flags are no longer exported

Between dpkg 1.14.17 and 1.16.1, B<dpkg-buildpackage>
exported compiler flags (B<CFLAGS>, B<CXXFLAGS>, B<FFLAGS>,
B<CPPFLAGS> and B<LDFLAGS>) with values as returned
by B<dpkg-buildflags>.
This is no longer the case.

=head2 Default build targets

B<dpkg-buildpackage> is using the B<build-arch> and
B<build-indep> targets since dpkg 1.16.2.
Before dpkg 1.22.7,
there was code to try to detect the missing targets and fallback on the
B<build> target.
Those targets are thus mandatory.

=head1 SECURITY

Building binary or source packages should only be performed over trusted
source data.

=head1 BUGS

It should be possible to specify spaces and shell metacharacters
and initial arguments for
I<gain-root-command> and I<sign-command>.

=head1 SEE ALSO

I<%PKGDOCDIR%/spec/rootless-builds.txt>,
L<dpkg-source(1)>,
L<dpkg-architecture(1)>,
L<dpkg-buildflags(1)>,
L<dpkg-genbuildinfo(1)>,
L<dpkg-genchanges(1)>,
L<fakeroot(1)>,
L<lintian(1)>,
L<SOP|https://datatracker.ietf.org/doc/draft-dkg-openpgp-stateless-cli/>,
L<sq(1)>,
L<gpg(1)>.
