Conditional compilation depending on CONFIG_FOOBAR
Hi, I want to conditionally compile some code in module if CONFIG_FOOBAR is defined. How can I add this check to my module's makefile? -Thanks.
Just to clarify more, if I put my code in something like: #ifdef CONFIG_FOOBAR my code #endif Then my module's Makefile should check if this parameter is defined in the ".config" file. How should I modify my Makefile to do that? On Sun, Dec 11, 2011 at 10:44 PM, contemplating zombie < contemplatingzombie@gmail.com> wrote:
Hi,
I want to conditionally compile some code in module if CONFIG_FOOBAR is defined. How can I add this check to my module's makefile?
-Thanks.
On Mon, Dec 12, 2011 at 9:17 AM, contemplating zombie < contemplatingzombie@gmail.com> wrote:
Just to clarify more, if I put my code in something like: #ifdef CONFIG_FOOBAR my code #endif
Then my module's Makefile should check if this parameter is defined in the ".config" file. How should I modify my Makefile to do that?
On Sun, Dec 11, 2011 at 10:44 PM, contemplating zombie < contemplatingzombie@gmail.com> wrote:
Hi,
I want to conditionally compile some code in module if CONFIG_FOOBAR is defined. How can I add this check to my module's makefile?
-Thanks.
If I understand correctly, you want some part of your module to be compiled only when CONFIG_FOOBAR is defined. You already mentioned the solution yourself!: Just put that code within #ifdef CONFIG_FOOBAR and #endif That would check the .config file and see if CONFIG_FOOBAR is defined; and only if it is defined, that code piece gets compiled, else it will simply get stripped off. Regards, Srivatsa S. Bhat
On Mon, Dec 12, 2011 at 8:59 AM, Srivatsa Bhat <bhat.srivatsa@gmail.com> wrote:
On Mon, Dec 12, 2011 at 9:17 AM, contemplating zombie <contemplatingzombie@gmail.com> wrote:
Just to clarify more, if I put my code in something like: #ifdef CONFIG_FOOBAR my code #endif
Then my module's Makefile should check if this parameter is defined in the ".config" file. How should I modify my Makefile to do that?
On Sun, Dec 11, 2011 at 10:44 PM, contemplating zombie <contemplatingzombie@gmail.com> wrote:
Hi,
I want to conditionally compile some code in module if CONFIG_FOOBAR is defined. How can I add this check to my module's makefile?
-Thanks.
If I understand correctly, you want some part of your module to be compiled only when CONFIG_FOOBAR is defined. You already mentioned the solution yourself!: Just put that code within #ifdef CONFIG_FOOBAR and #endif That would check the .config file and see if CONFIG_FOOBAR is defined; and only if it is defined, that code piece gets compiled, else it will simply get stripped off.
Now if the question is _how_ to define the configuration symbol FOOBAR. Then you have to add a new configuration option to a Kconfig file (probably the one that exists in the directory where you have the file that is using it). For example, suppose that you have a char device driver located in drivers/char/yourdev.c and yourdev uses a FOOBAR option to do something. Then you have to add something like this in drivers/char/Kconfig config FOOBAR bool "decide to use foobar or not" help Say Y here if you want to enable the foobar option. When you execute make menuconfig or other make targets that generate the compilation options menu. You will see your option under "Device drivers" -> "Character devices" The mconf binary will write in .config the value that you chose for FOOBAR and will append CONFIG_ So if you enable FOOBAR, you will have something like: CONFIG_FOOBAR=y Then this symbols are used to create a generated autoconf.h file in include/generated/autoconf.h every compilation command in the kernel includes this file gcc yourdev.c -I include/generated/autoconf.h For a detailed description of the kernel build system look at Documentation/kbuild/ Hope it helps, -- Javier Martínez Canillas (+34) 682 39 81 69 Barcelona, Spain
participants (3)
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contemplating zombie -
Javier Martinez Canillas -
Srivatsa Bhat