Dovecots header files not optimized for external plugins

[Timo Sirainen]

On 19 Nov 2017, at 0.40, Jan Engelhardt <jengelh at inai.de> wrote:
> 
> 
> Making third-party plugins for Dovecot is really hard and frustrating.
> Using dovecot 2.2.33.2 and the following sources, the compile errors keep
> coming. The use of g++ is mandated as the underlying backend this plugin
> will access only has a C++ interface.

See compile instructions for example here: https://dovecot.org/patches/2.2/imap-logout-plugin.c <https://dovecot.org/patches/2.2/imap-logout-plugin.c>

> == Problems 2
> In file included from /usr/include/bits/byteswap.h:35:0,
>                 from /usr/include/byteswap.h:24,
>                 from a.cpp:2:
> /usr/include/dovecot/byteorder.h:32:24: error: expected unqualified-id before ‘__extension__’
> static inline uint16_t bswap_16(uint16_t in);

Try #undef bswap_16 (and others)? We have a patch pending that does these #undefs to fix compiling issue with uclibc-ng - maybe a similar problem.

> == Other problems
> dovecot headers files are missing 'extern "C"' lines.
> This means the linkage of symbols like dev_null_fd is not what it should be.
> I can't use
> extern "C" {
> #include <dovecot/...>
> }
> either because then the standardy library headers that are included
> by dovecot headers can easily start acting up too.


lucene-wrapper.cc seems to compile fine with this..