Re: [PATCH] iio: Use type header from kernel tree

From: Laura Abbott
Date: Fri Sep 09 2016 - 11:48:01 EST


On 09/09/2016 08:35 AM, Daniel Baluta wrote:
On Fri, Sep 9, 2016 at 6:24 PM, Laura Abbott <labbott@xxxxxxxxxx> wrote:

The iio tools have been updated as new event types have been added to
the kernel. The tools currently use the standard system headers which
means that the system may not have the newest defintitions. This leads
to build failures when building newer tools on older hosts:

gcc -Wall -g -D_GNU_SOURCE -c -o iio_event_monitor.o
iio_event_monitor.c
iio_event_monitor.c:59:3: error: âIIO_UVINDEXâ undeclared here (not in a
function)
[IIO_UVINDEX] = "uvindex",
^~~~~~~~~~~
iio_event_monitor.c:59:3: error: array index in initializer not of
integer type
iio_event_monitor.c:59:3: note: (near initialization for
âiio_chan_type_name_specâ)
iio_event_monitor.c:97:3: error: âIIO_MOD_LIGHT_UVâ undeclared here (not
in a function)
[IIO_MOD_LIGHT_UV] = "uv",
^~~~~~~~~~~~~~~~
iio_event_monitor.c:97:3: error: array index in initializer not of
integer type
iio_event_monitor.c:97:3: note: (near initialization for
âiio_modifier_namesâ)
<builtin>: recipe for target 'iio_event_monitor.o' failed

Switch to using the header from the kernel tree to ensure the newest
defintions are always picked up.

Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>

Hi Laura,

Thanks for your patch. The solution here would be to install the
headers for your
new kernel in order to use the updated types.

That is you should run make headers_install.

$ make help | grep headers
headers_install - Install sanitised kernel headers to INSTALL_HDR_PATH

You can use INSTALL_HDR_PATH to put the headers in a custom directory
and tell gcc to also include this directory when searching for include headers.


That's a pretty ugly solution. We want to build this as part of Fedora
and installing another local copy of the headers in the build environment
complicates an already complicated build process. This is more work
for users building on their own as well. Several other tools in the tools
directory already use the headers from the kernel tree, is there a reason
iio doesn't want to as well?

Thanks,
Laura