-Wundef warning

[simark]

When building with -Wundef, we get this diagnostic

$ cmake .. -DCMAKE_C_FLAGS="-Wundef"
-- Configuring done
-- Generating done
-- Build files have been written to: /home/smarchi/src/zf_log/build
$ make
[ 50%] Building C object zf_log/CMakeFiles/zf_log.dir/zf_log.c.o
/home/smarchi/src/zf_log/zf_log/zf_log.c: In function ‘put_tag’:
/home/smarchi/src/zf_log/zf_log/zf_log.c:452:15: error: "_ZF_LOG_MESSAGE_FORMAT_MASK__TAG" is not defined, evaluates to 0 [-Werror=undef]
  _PP_CONCAT_3(_ZF_LOG_MESSAGE_FORMAT_MASK_, _, field)
               ^
/home/smarchi/src/zf_log/zf_log/zf_log.c:347:30: note: in definition of macro ‘_PP_PASTE_3’
 #define _PP_PASTE_3(a, b, c) a ## b ## c
                              ^
/home/smarchi/src/zf_log/zf_log/zf_log.c:452:2: note: in expansion of macro ‘_PP_CONCAT_3’
  _PP_CONCAT_3(_ZF_LOG_MESSAGE_FORMAT_MASK_, _, field)
  ^~~~~~~~~~~~
/home/smarchi/src/zf_log/zf_log/zf_log.c:467:3: note: in expansion of macro ‘_ZF_LOG_MESSAGE_FORMAT_MASK’
  (_ZF_LOG_MESSAGE_FORMAT_MASK(field) & _ZF_LOG_MESSAGE_FORMAT_FIELDS(format))
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/smarchi/src/zf_log/zf_log/zf_log.c:1159:6: note: in expansion of macro ‘_ZF_LOG_MESSAGE_FORMAT_CONTAINS’
 #if !_ZF_LOG_MESSAGE_FORMAT_CONTAINS(TAG, ZF_LOG_MESSAGE_TAG_FORMAT)
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I tried to investigate but quickly got lost in the macros. I believe that it might be important, as some value that's supposed to be a mask is actually 0.

[wonder-mice]

Yep, that's a good catch. I'll see what I can to fix it.