Commit a5247310 authored by Yann E. MORIN's avatar Yann E. MORIN Committed by Peter Korsgaard
Browse files

manual: add explanations on limitations about using O=... 



Using a relative path for O=... has limitations, since it is interpreted
relative to the Buildroot tree, and thus may lead to unexpected results.

For example, running this:
    make -C buildroot O=my-O

will not create my-O in the current working directory, but as a
sub-directory of the Buildroot tree, here in buildroot/my-O

Explain this in the manual (as is similarly done for BR2_EXTERNAL).
Also add a note that $(O) will be created if missing.

Also change O=.. and -C .. to O=<...> and -C <...> to make it explicit
this is an ellipse, not a relative path.

Reported-by: default avatarJérémy Rosen <jeremy.rosen@openwide.fr>
Signed-off-by: default avatar"Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Samuel Martin <s.martin49@gmail.com>
Reviewed-by: default avatarThomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Acked-by: default avatarSamuel Martin <s.martin49@gmail.com>
Signed-off-by: default avatarPeter Korsgaard <peter@korsgaard.com>
parent 1de64ec8

docs/manual/common-usage.txt

+9 −3
Original line number Diff line number Diff line
@@ -40,7 +40,13 @@ Or: 
 $ cd /tmp/build; make O=$PWD -C path/to/buildroot

--------------------



All the output files will be located under +/tmp/build+.

All the output files will be located under +/tmp/build+. If the +O+

path does not exist, Buildroot will create it.



*Note:* the +O+ path can be either an absolute or a relative path, but if it's

passed as a relative path, it is important to note that it is interpreted

relative to the main Buildroot source directory, *not* the current working

directory.



When using out-of-tree builds, the Buildroot +.config+ and temporary

files are also stored in the output directory. This means that you can
@@ -48,8 +54,8 @@ safely run multiple builds in parallel using the same source tree as 
long as they use unique output directories.



For ease of use, Buildroot generates a Makefile wrapper in the output

directory - so after the first run, you no longer need to pass +O=..+

and +-C ..+, simply run (in the output directory):

directory - so after the first run, you no longer need to pass +O=<...>+

and +-C <...>+, simply run (in the output directory):



--------------------

 $ make <target>