The close_range(2) man page says: close_range() first appeared in Linux 5.9. Library support was added in glibc in version 2.34.
The qemu-user GitLab CI jobs are failing. For example, see https://gitlab.com/qemu-project/qemu/-/jobs/3043629417: ../linux-user/syscall.c:8734:26: error: implicit declaration of function 'close_range' is invalid in C99 [-Werror,-Wimplicit-function-declaration] return get_errno(close_range(arg1, arg2, arg3)); ^ There is a second issue with this pull request: ../linux-user/syscall.c:357:16: error: ‘pidfd_getfd’ defined but not used [-Werror=unused-function] 357 | _syscall3(int, pidfd_getfd, int, pidfd, int, targetfd, unsigned int, flags); | ^~~~~~~~~~~ ../linux-user/syscall.c:251:13: note: in definition of macro ‘_syscall3’ See https://gitlab.com/qemu-project/qemu/-/jobs/3043629434. Stefan