On 04/23/2018 01:16 PM, Peter Maydell wrote: > On 23 April 2018 at 17:10, Murilo Opsfelder Araujo > <muri...@linux.ibm.com> wrote: >> Hi, everyone! >> >> I'm facing an issue on how configure script detects static libraries and >> would like to hear from community to find a common ground on how to >> possibly fix it. >> >> Throughout configure, we use pkg-config command to verify if a library >> is installed so qemu can be linked to it. This works fine when linking >> qemu dynamically. However, configuring qemu with --static can mistakenly >> detect a library that is actually not present on the system. >> >> For example, on Ubuntu Xenial, libcacard-dev package provides only >> libcacard.so (not libcacard.a) and pkg-config reports success in both >> cases: >> >> $ pkg-config libcacard >> $ echo $? >> 0 >> >> $ pkg-config --static libcacard >> $ echo $? >> 0 >> >> Since we use `pkg-config libcacard` to set smartcard=yes, this >> mistakenly enables smartcard feature. This is acceptable with dynamic >> linkage, but can be an issue with static linkage, where libcacard.a >> doesn't exist on the system, resulting on a build error: > > This seems to me to be an error in your distro's pkg-config information. > If static linking against libcacard doesn't work, then > "pkg-config --static libcacard" should fail.
I see in man(1) pkg-config that --static is merely used to compute deeper dependency graph intended for static linking. Since <package>.pc is present, pkg-config assumes the library exists and --static is merely informational. Do you think this should be reported to pkg-config project? > Unfortunately IME the static linking support in distro-suppled > pkgconfig files is rarely tested, so it's not uncommon for it to > be broken. > > From an upstream QEMU point of view, we primarily support --static > for the benefit of the linux-user binaries, not for system emulation. > So we care more if a "configure --disable-system --disable-tools --static" > build doesn't work, than if the problem is only with features used > by the system emulator binaries. In this case, shouldn't we update configure script to emit a warning message to user saying it's running a non-supported scenario when --static is given without --disable-system and --disable-tools? > thanks > -- PMM > Cheers Murilo
