On Thu, Sep 21, 2023 at 12:08:33PM -0400, Anass Meskini via curl-library wrote: > Thanks Dan for the clarification. > I think it might be worth mentioning in the doc that this function might > create > a thread.
It is called the "threaded resolver" after all, and that name is found in 8 different documentation files in the source tree, including in libcurl-thread(3) which is the go-to location for information about threading in libcurl. Where else would you like to see it? curl_multi_perform(3) seems like a poor place for it, because *absolutely everything* happens in a call to curl_multi_perform and we can't document everything there. > Would setting CURLOPT_RESOLVE result in curl_multi_perform never creating a > new > thread? I'm pretty sure that the name resolve cache is checked before the system resolver thread is created, so this should work. > Also when I run multi-app.c in helgrind, I see: > > ==339231== > ---Thread-Announcement------------------------------------------ > ==339231== > ==339231== Thread #1 is the program's root thread > ==339231== > ==339231== > ---------------------------------------------------------------- > ==339231== > ==339231== Thread #1: pthread_mutex_destroy with invalid argument > ==339231== at 0x483FC96: ??? (in /usr/lib/x86_64-linux-gnu/valgrind/ > vgpreload_helgrind-amd64-linux.so) > ==339231== by 0x572D16F: ??? (in /usr/lib/x86_64-linux-gnu/ > libp11-kit.so.0.3.0) > ==339231== by 0x4011F6A: _dl_fini (dl-fini.c:138) > ==339231== by 0x49468A6: __run_exit_handlers (exit.c:108) > ==339231== by 0x4946A5F: exit (exit.c:139) > ==339231== by 0x4924089: (below main) (libc-start.c:342) > ==339231== > ==339231== > ---------------------------------------------------------------- > ==339231== > ==339231== Thread #1: pthread_mutex_destroy with invalid argument > ==339231== at 0x483FC96: ??? (in /usr/lib/x86_64-linux-gnu/valgrind/ > vgpreload_helgrind-amd64-linux.so) > ==339231== by 0x4011F6A: _dl_fini (dl-fini.c:138) > ==339231== by 0x49468A6: __run_exit_handlers (exit.c:108) > ==339231== by 0x4946A5F: exit (exit.c:139) > ==339231== by 0x4924089: (below main) (libc-start.c:342) > > > Are these false positives? Not that I'm aware. Note that libcurl uses pthread mutexes aside from threading, so these a not (necessarily) related to the threaded resolver. Other libraries like OpenSSL, GnuTLS and libssh also uses mutexes, so this might not ever be an issue in libcurl. Dan -- Unsubscribe: https://lists.haxx.se/mailman/listinfo/curl-library Etiquette: https://curl.se/mail/etiquette.html
