dpkg-architecture(1)						  dpkg utilities					      dpkg-architecture(1)

NAME

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

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							    2012-01-20						      dpkg-architecture(1)