Manual Reference Pages  - dpkg-architecture (1)

NAME

dpkg-architecture - set and determine the architecture for package building

CONTENTS

Description
Commands
Options
Terms
Variables
Examples
Files

SYNOPSIS

dpkg-architecture [option...] [command]

DESCRIPTION

dpkg-architecture does provide a facility to determine and set the build and host architecture for package building.

The build architecture is always determined by an external call to dpkg(1), and can not be set at the command line.

You can specify the host architecture by providing one or both of the options -a and -t. The default is determined by an external call to gcc(1), or the same as the build architecture if CC or gcc are both not available. One out of -a and -t is sufficient, the value of the other will be set to a usable default. Indeed, it is often better to only specify one, because dpkg-architecture will warn you if your choice does not match the default.

COMMANDS

-l Print the environment variables, one each line, in the format VARIABLE=value. This is the default action.
-edebian-architecture
  Check for equality of architecture. By default debian-architecture is compared against the current Debian architecture, being the host. This action will not expand the architecture wildcards. Command finishes with an exit status of 0 if matched, 1 if not matched.
-iarchitecture-wildcard
  Check for identity of architecture by expanding architecture-wildcard as an architecture wildcard and comparing against the current Debian architecture. Command finishes with an exit status of 0 if matched, 1 if not matched.
-qvariable-name
  Print the value of a single variable.
-s Print an export command. This can be used to set the environment variables using eval.
-u Print a similar command to -s but to unset all variables.
-c command
  Execute a command in an environment which has all variables set to the determined value.
-L Print a list of valid architecture names.
-?, --help
  Show the usage message and exit.
--version
  Show the version and exit.

OPTIONS

-adebian-architecture
  Set the Debian architecture.
-tgnu-system-type
  Set the GNU system type.
-f Values set by existing environment variables with the same name as used by the scripts are honored (i.e. used by dpkg-architecture), except if this force flag is present. This allows the user to override a value even when the call to dpkg-architecture is buried in some other script (for example dpkg-buildpackage(1)).

TERMS

build machine The machine the package is built on.
host machine The machine the package is built for.
Debian architecture The Debian architecture string, which specifies the binary tree in the FTP archive. Examples: i386, sparc, hurd-i386.
architecture wildcard An architecture wildcard is a special architecture string that will match any real architecture being part of it. The general form is <kernel>-<cpu>. Examples: linux-any, any-i386, hurd-any.
GNU system type An architecture specification string consisting of two parts separated by a dash: cpu and system. Examples: i386-linux-gnu, sparc-linux-gnu, i386-gnu, x86_64-netbsd.

VARIABLES

The following variables are set by dpkg-architecture:
DEB_BUILD_ARCH The Debian architecture of the build machine.
DEB_BUILD_ARCH_OS The Debian system name of the build machine.
DEB_BUILD_ARCH_CPU The Debian cpu name of the build machine.
DEB_BUILD_ARCH_BITS The pointer size of the build machine (in bits).
DEB_BUILD_ARCH_ENDIAN The endianness of the build machine (little / big).
DEB_BUILD_GNU_CPU The CPU part of DEB_BUILD_GNU_TYPE.
DEB_BUILD_GNU_SYSTEM The System part of DEB_BUILD_GNU_TYPE.
DEB_BUILD_GNU_TYPE The GNU system type of the build machine.
DEB_BUILD_MULTIARCH The clarified GNU system type of the build machine, used for filesystem paths.
DEB_HOST_ARCH The Debian architecture of the host machine.
DEB_HOST_ARCH_OS The Debian system name of the host machine.
DEB_HOST_ARCH_CPU The Debian cpu name of the host machine.
DEB_HOST_ARCH_BITS The pointer size of the host machine (in bits).
DEB_HOST_ARCH_ENDIAN The endianness of the host machine (little / big).
DEB_HOST_GNU_CPU The CPU part of DEB_HOST_GNU_TYPE.
DEB_HOST_GNU_SYSTEM The System part of DEB_HOST_GNU_TYPE.
DEB_HOST_GNU_TYPE The GNU system type of the host machine.
DEB_HOST_MULTIARCH The clarified GNU system type of the host machine, used for filesystem paths.

DEBIAN/RULES

The environment variables set by dpkg-architecture are passed to debian/rules as make variables (see make documentation). However, you should not rely on them, as this breaks manual invocation of the script. Instead, you should always initialize them using dpkg-architecture with the -q option. Here are some examples, which also show how you can improve the cross compilation support in your package:

Retrieving the GNU system type and forwarding it to ./configure:
DEB_BUILD_GNU_TYPE := $(shell dpkg-architecture -qDEB_BUILD_GNU_TYPE)
DEB_HOST_GNU_TYPE := $(shell dpkg-architecture -qDEB_HOST_GNU_TYPE)
[...]
configure --build=$(DEB_BUILD_GNU_TYPE) --host=$(DEB_HOST_GNU_TYPE)

Doing something only for a specific architecture:

DEB_HOST_ARCH := $(shell dpkg-architecture -qDEB_HOST_ARCH)

ifeq ($(DEB_HOST_ARCH),alpha) [...] endif

or if you only need to check the CPU or OS type, use the DEB_HOST_ARCH_CPU or DEB_HOST_ARCH_OS variables.
Note that you can also rely on an external Makefile snippet to properly set all the variables that dpkg-architecture can provide:
include /usr/share/dpkg/architecture.mk

ifeq ($(DEB_HOST_ARCH),alpha) [...] endif

In any case, you should never use dpkg --print-architecture to get architecture information during a package build.

BACKWARD COMPATIBILITY

The /usr/share/dpkg/architecture.mk Makefile snippet is provided by dpkg-dev since version 1.16.1.

The DEB_*_ARCH_BITS and DEB_*_ARCH_ENDIAN variables were introduced in dpkg-dev 1.15.4. Using them in debian/rules thus requires a build-dependency on dpkg-dev (>= 1.15.4).

The DEB_HOST_ARCH_CPU and DEB_HOST_ARCH_OS variables were introduced in dpkg-dev 1.13.2.

The -e and -i options were only introduced in relatively recent versions of dpkg-architecture (since dpkg 1.13.13).

EXAMPLES

dpkg-buildpackage accepts the -a option and passes it to dpkg-architecture. Other examples:
CC=i386-gnu-gcc dpkg-architecture -c debian/rules build
eval `dpkg-architecture -u`
Check if an architecture is equal to the current architecture or a given one:
dpkg-architecture -elinux-alpha
dpkg-architecture -amips -elinux-mips
Check if the current architecture or an architecture provided with -a are Linux systems:
dpkg-architecture -ilinux-any
dpkg-architecture -ai386 -ilinux-any

FILES

All these files have to be present for dpkg-architecture to work. Their location can be overridden at runtime with the environment variable DPKG_DATADIR.
/usr/share/dpkg/cputable
  Table of known CPU names and mapping to their GNU name.
/usr/share/dpkg/ostable
  Table of known operating system names and mapping to their GNU name.
/usr/share/dpkg/triplettable
  Mapping between Debian architecture triplets and Debian architecture names.

SEE ALSO

dpkg-buildpackage(1), dpkg-cross(1).


Debian Project dpkg-architecture (1) 2012-01-20
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