a90382616c
Consider the second chapter: "starting-up", as a tutorial. Assuming that, using.txt only contains the very first commands used to get configure and build its very first target system. So, the following subsection from using.txt have been to common-usage.txt: - Offline builds - Building out-of-tree - Environment variables Signed-off-by: Samuel Martin <s.martin49@gmail.com> Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
102 lines
3.0 KiB
Plaintext
102 lines
3.0 KiB
Plaintext
// -*- mode:doc; -*-
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Daily use
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---------
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include::rebuilding-packages.txt[]
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Offline builds
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~~~~~~~~~~~~~~
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If you intend to do an offline build and just want to download
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all sources that you previously selected in the configurator
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('menuconfig', 'xconfig' or 'gconfig'), then issue:
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--------------------
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$ make source
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--------------------
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You can now disconnect or copy the content of your +dl+
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directory to the build-host.
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Building out-of-tree
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~~~~~~~~~~~~~~~~~~~~
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As default, everything built by Buildroot is stored in the directory
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+output+ in the buildroot tree.
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Buildroot also supports building out of tree with a syntax similar to
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the Linux kernel. To use it, add +O=<directory>+ to the make command
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line:
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--------------------
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$ make O=/tmp/build
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--------------------
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Or:
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--------------------
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$ cd /tmp/build; make O=$PWD -C path/to/buildroot
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--------------------
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All the output files will be located under +/tmp/build+.
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When using out-of-tree builds, the Buildroot +.config+ and temporary
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files are also stored in the output directory. This means that you can
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safely run multiple builds in parallel using the same source tree as
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long as they use unique output directories.
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For ease of use, Buildroot generates a Makefile wrapper in the output
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directory - So after the first run, you no longer need to pass +O=..+
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and +-C ..+, simply run (in the output directory):
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--------------------
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$ make <target>
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--------------------
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[[env-vars]]
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Environment variables
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~~~~~~~~~~~~~~~~~~~~~
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Buildroot also honors some environment variables, when they are passed
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to +make+ or set in the environment:
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* +HOSTCXX+, the host C++ compiler to use
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* +HOSTCC+, the host C compiler to use
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* +UCLIBC_CONFIG_FILE=<path/to/.config>+, path to
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the uClibc configuration file, used to compile uClibc, if an
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internal toolchain is being built.
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+
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Note that the uClibc configuration file can also be set from the
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configuration interface, so through the Buildroot .config file; this
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the actual recommended way of setting it.
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+
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* +BUSYBOX_CONFIG_FILE=<path/to/.config>+, path to
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the Busybox configuration file.
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+
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Note that the Busybox configuration file can also be set from the
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configuration interface, so through the Buildroot .config file; this
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the actual recommended way of setting it.
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+
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* +BUILDROOT_DL_DIR+ to override the directory in which
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Buildroot stores/retrieves downloaded files
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+
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Note that the Buildroot download directory can also be set from the
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configuration interface, so through the Buildroot .config file; this
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the actual recommended way of setting it.
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An example that uses config files located in the toplevel directory and
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in your $HOME:
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$ make UCLIBC_CONFIG_FILE=uClibc.config BUSYBOX_CONFIG_FILE=$HOME/bb.config
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--------------------
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If you want to use a compiler other than the default +gcc+
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or +g+++ for building helper-binaries on your host, then do
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$ make HOSTCXX=g++-4.3-HEAD HOSTCC=gcc-4.3-HEAD
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--------------------
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