[sane-devel] [PATCH] undef linux before defining STRINGIFY

[Niels Ole Salscheider]

Am 2015-06-09 14:21, schrieb m. allan noah:
> We need more info here. Where do you see this expansion problem?
> 
> allan

The problem is that LIBDIR is passed as a define from the build system.
Then, STRINGIFY(LIBDIR) is used in backend/dll.c to get a string of the 
search path for the backends.
This seems to be fine but it can become a problem since "linux" is 
definded to "1" by default.

This causes an issue on e. g. Exherbo, my linux distribution. Exherbo 
installs all packages to /usr/target-triplet/{bin,lib,include,...} so 
that you can have packages for different architectures on the same root. 
On my system, sane would be installed to /usr/x86_64-pc-linux-gnu/..., 
so that LIBDIR would be defined to be /usr/x86_64-pc-linux-gnu/lib.
But now, STRINGIFY(LIBDIR) turns this into /usr/x86_64-pc-1-gnu/lib 
(since it also expands linux) - and as a result, sane cannot find any 
backends.

Ole

> On Sun, Jun 7, 2015 at 4:14 PM, Niels Ole Salscheider
> <niels_ole at salscheider-online.de> wrote:
>> Otherwise, "linux" will be expanded to "1" when it is stringified.
>> 
>> This is a problem for e. g. LIBDIR, which might contain a target 
>> triplet.
>> On my system, /usr/x86_64-pc-linux-gnu-gcc would expand to 
>> x86_64-pc-1-gnu-gcc.
>> ---
>>  include/sane/sanei.h | 3 +++
>>  1 file changed, 3 insertions(+)
>> 
>> diff --git a/include/sane/sanei.h b/include/sane/sanei.h
>> index ece1beb..90ec028 100644
>> --- a/include/sane/sanei.h
>> +++ b/include/sane/sanei.h
>> @@ -140,6 +140,9 @@
>>  /** @hideinitializer */
>>  #define NELEMS(a)      ((int)(sizeof (a) / sizeof (a[0])))
>> 
>> +/* undef linux so that it can be stringified. It would expand to 1 
>> otherwise. */
>> +#undef linux
>> +
>>  /** @hideinitializer */
>>  #define STRINGIFY1(x)  #x
>>  /** @hideinitializer */
>> --
>> 2.4.2
>> 
>> 
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