nx_flock.nx

nx_flock.nx -- BSD-style file locking via flock(2). Two flavors of file locking on Linux: 1. flock(2) -- whole-file advisory lock, simpler, less powerful 2. fcntl(2) F_SETLK -- byte-range lock, more flexible This module covers (1). flock() is what most build tools and daemons use: - Lockfile to prevent two builds from running concurrently - Daemon PID file lock (acquire on startup, release at exit) - Crash-safe single-instance enforcement Linux RV64 syscall: 32 (flock). Lock types: LOCK_SH shared (read) lock LOCK_EX exclusive (write) lock LOCK_UN unlock LOCK_NB non-blocking (OR with one of the above)