Undefined reference when trying to use lt::dht::generate_random_id()

[AaronBeier]

Hi. As the title suggests i'm trying to use lt::dht::generate_random_id() but get

/usr/bin/ld: /tmp/ccgEmPxE.ltrans0.ltrans.o: in function `main':
<artificial>:(.text.startup+0x13b9): undefined reference to `libtorrent::dht::generate_random_id()'
/usr/bin/ld: <artificial>:(.text.startup+0x16f9): undefined reference to `libtorrent::dht::generate_random_id()'
collect2: error: ld returned 1 exit status

when trying to compile my program. I found #7447 which mentions i need to set TORRENT_USE_LIBCRYPTO for openssl. I'm on arch linux and the pkgfile requires openssl so i assume libcrypto iis what i want: https://gitlab.archlinux.org/archlinux/packaging/packages/libtorrent-rasterbar/-/blob/main/PKGBUILD?ref_type=heads
Adding -lcrypto and -lssl does nothing. I've also tried defining that at the top of my code and in my gcc command via -D but still get the error. Any ideas? I'd be fine with switching to cmake if that would make it easier.

[arvidn]

generate_random_id() is not exposed as part of libtorrent's API. I take it you're linking against libtorrent as a shared library and expect to find this function available to you. It's not. It (probably) works if you link statically against libtorrent. You can also force this function to be exported by building libtorrent in test-mode, where functions that ordinarilly aren't exported are, in order to test them.

You can do that by defining TORRENT_EXPORT_EXTRA as part of the build, or passing export-extra=on to the b2 command line.