dpkg-architecture (1)

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 (since dpkg 1.13.13). 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 (since dpkg 1.13.13). 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 hyphen: 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 (since dpkg 1.13.2).
DEB_BUILD_ARCH_CPU: The Debian cpu name of the build machine (since dpkg 1.13.2).
DEB_BUILD_ARCH_BITS: The pointer size of the build machine (in bits; since dpkg 1.15.4).
DEB_BUILD_ARCH_ENDIAN: The endianness of the build machine (little / big; since dpkg 1.15.4).
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 (since dpkg 1.16.0).
DEB_HOST_ARCH: The Debian architecture of the host machine.
DEB_HOST_ARCH_OS: The Debian system name of the host machine (since dpkg 1.13.2).
DEB_HOST_ARCH_CPU: The Debian cpu name of the host machine (since dpkg 1.13.2).
DEB_HOST_ARCH_BITS: The pointer size of the host machine (in bits; since dpkg 1.15.4).
DEB_HOST_ARCH_ENDIAN: The endianness of the host machine (little / big; since dpkg 1.15.4).
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 (since dpkg 1.16.0).

FILES

Architecture tables

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.

Packaging support

/usr/share/dpkg/architecture.mk: Makefile snippet that properly sets and exports all the variables that dpkg-architecture outputs (since dpkg 1.16.1).

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

Usage in 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 ?= $(shell dpkg-architecture -qDEB_HOST_GNU_TYPE)
[...]
ifeq ($(DEB_BUILD_GNU_TYPE), $(DEB_HOST_GNU_TYPE))
  confflags += --build=$(DEB_HOST_GNU_TYPE)
else
  confflags += --build=$(DEB_BUILD_GNU_TYPE) \
               --host=$(DEB_HOST_GNU_TYPE)
endif
[...]
./configure $(confflags)

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.

dpkg-architecture (1)

Contents

NAME

SYNOPSIS

DESCRIPTION