runtime - what the program can know about the machine it runs on.
Only what a shared object can answer on its own. The numbers of the interpreter itself, how many tau routines are alive or how full the heap is, are private to it and no shared object can reach them.
¶NumCPU = fn()source
NumCPU returns how many cores the program may run on, which is the number to size a pool of tau routines with. It never returns less than 1.
¶OS = fn()source
OS returns the system this was built for, named the way Go names it: "linux", "darwin", "windows", "freebsd", "openbsd", "netbsd".
¶Arch = fn()source
Arch returns the architecture this was built for, again named the way Go names it: "amd64", "arm64", "386", "arm", "riscv64".