On Wed, Aug 03, 2022, Andrew Jones wrote: > On Wed, Aug 03, 2022 at 09:58:51PM +0800, Jinrong Liang wrote: > > My ldd version is (GNU libc) 2.28, and I get a compilation error in this case. > > But I use another ldd (Ubuntu GLIBC 2.31-0ubuntu9.2) 2.31 is compiling fine. > > This shows that compilation errors may occur in different GNU libc environments. > > Would it be more appropriate to use syscall for better compatibility? > > OK, it's a pity, but no big deal to use syscall(). Ya, https://man7.org/linux/man-pages/man2/gettid.2.html says: The gettid() system call first appeared on Linux in kernel 2.4.11. Library support was added in glibc 2.30. But there are already two other instances of syscall(SYS_gettid) in KVM selftests, tools/testing/selftests/kvm/lib/assert.c even adds a _gettid() wrapper. So rather than having to remember (or discover) to use syscall(SYS_gettid), I wonder if it's possible to conditionally define gettid()? E.g. check for GLIBC version? Or do #define gettid() syscall(SYS_gettid) so that it's always available and simply overrides the library's gettid() if it's provided?
