The default build (make MODE=) has logging enabled (so do the release binaries). If any system calls are missing, then Blink will return ENOSYS to the program a

The default build (make MODE=) has logging enabled (so do the release binaries). If any system calls are missing, then Blink will return ENOSYS to the program and then create a "blink.log" file in the current directory reporting that, e.g. master jart@nightmare:~/cosmo$ blink ruby --yjit -e 'printf("%d\n",2+2)' <main>: warning: timer_create failed: Function not implemented, signals racy 4 master jart@nightmare:~/cosmo$ cat blink.log I2023-06-05T04:22:15.525179:blink/syscall.c:1020:29575 unsupported prctl op 0x29 I2023-06-05T04:22:15.556803:blink/syscall.c:5720:29575 missing syscall 0x122 I2023-06-05T04:22:15.556866:blink/syscall.c:5720:29575 missing syscall 0x122 I2023-06-05T04:22:15.556886:blink/syscall.c:5720:29575 missing syscall 0x0de You can also use `blink -es program...` to log system calls to stderr, similar to strace, when you need to troubleshoot further. Once you do that, please file a feature request.