Paz Offer <pof...@nvidia.com> writes: > ...after some testing... > [Trying to add 'libdl' to be linked with QEMU] > > I did try to use 'g_module_open/close/symbol', but what I noticed is that > 'g_module_close' did not really unload my library. > So if I would do: > > 1 g_module_open(my-lib) > 2 Load symbols, use my library... > 3 g_module_close(my-lib) > 4 Make modifications to my library and reload it: > 5 g_module_open(my-lib) > > Then the library was not really reloaded, and the old instance would > still be used.
Glib does do reference counting so it won't unload the module until all references have been dropped. Did you check the return value from the g_module_close()? > This did not happen when I used dlopen/dlclose. > Do we have a way to force 'g_module_close' to unload the library? On POSIX the underlying mechanism is dlclose() anyway. You can also check g_module_error() to see if there was an error unloading. > > Thanks, Paz > > ------------------------------------------------------------------------------------------------------------------------- > From: Peter Maydell <peter.mayd...@linaro.org> > Sent: Thursday, February 29, 2024 7:34 PM > To: Paz Offer <pof...@nvidia.com> > Cc: qemu-devel@nongnu.org <qemu-devel@nongnu.org> > Subject: Re: What is the correct way to add linker dependency to QEMU build > system? > > External email: Use caution opening links or attachments > > On Thu, 29 Feb 2024 at 16:10, Paz Offer <pof...@nvidia.com> wrote: >> I want to add library 'libdl' to be linked with QEMU build for a particular >> target (e.g. - qemu-system-arm). >> Using meson I would typically do 'compiler.find_library(...)', and later add >> the returned dependency to the binary > dependencies list. >> However, in QEMU I understand that these configurations are done in the >> './configure' file? >> >> What would be the correct way to do this? > > If you can do the job using the glib g_module_open()/ > g_module_symbol() functions (which is how QEMU itself does > loading of plugin and module DLLs, and which on Unix hosts > are pretty much wrappers around dlopen/dlsym) then you > don't need to link against libdl at all. > > If this is for something you're planning to upstream > then it might be worth talking at a higher level about > what you're aiming to do. (If it's for something downstream > that you don't plan to ever upstream then you can do > whatever's easiest for you, of course.) > > -- PMM -- Alex Bennée Virtualisation Tech Lead @ Linaro
