boost url does not build in single thread

[ropieur]

Hi,
I am wondering the reason why boost url couldn't be used in single threaded.
Woudn't be possible to allow building it in single thread?
Thank you

[pdimov]

What specific issue are you having?

[ropieur]

Our internal crosscompiler mingw32 (single thread compiler) complaints about std::mutex.

10:20:19  In file included from ./boost/url/grammar/impl/range_rule.hpp:16,
10:20:19                   from ./boost/url/grammar/range_rule.hpp:600,
10:20:19                   from ./boost/url/grammar.hpp:29,
10:20:19                   from ./boost/url.hpp:13,
10:20:19                   from ./boost/url/src.hpp:28,
10:20:19                   from libs/url/src/src.cpp:10:
10:20:19  ./boost/url/grammar/recycled.hpp:108:10: error: 'mutex' in namespace 'std' does not name a type
10:20:19    108 |     std::mutex m_;
10:20:19        |          ^~~~~
10:20:19  ./boost/url/grammar/recycled.hpp:19:1: note: 'std::mutex' is defined in header '<mutex>'; did you forget to '#include <mutex>'?
10:20:19     18 | #include <stddef.h> // ::max_align_t
10:20:19    +++ |+#include <mutex>
10:20:19     19 | 

[vinniefalco]

Alan, some notes for fixing this:

mutex doesn't work in a single threaded build of libstdc++. you need to, say, provide a macro disabling the mutex in single threaded mode like BOOST_SYSTEM_DISABLE_THREADS:

boostorg/system@53c0084

[ropieur]

Thank you @vinniefalco . May I expect to see this improvement in the next release of boost (1.82.0) ?

[vinniefalco]

Yes

[ropieur]

Great to hear. I close the ticket.

[vinniefalco]

Well lets keep it open so Alan knows to work on it :)

[alandefreitas]

@ropieur could you try this branch? This implementation uses BOOST_SYSTEM_DISABLE_THREADS as a reference.

(I'm duplicating #689 (comment) in case @ropieur is getting notifications from the issue only)

[ropieur]

@alandefreitas,
Thank you for the fix. Sorry for the delay. I will check internally how we can verify the branch.