module main import os import time import os.cmdline enum Target { both stderr stdout alternate } fn s2target(s string) Target { return match s { 'both' { Target.both } 'stderr' { Target.stderr } 'alternate' { Target.alternate } else { Target.stdout } } } struct Context { mut: timeout_ms int period_ms int exitcode int target Target omode Target is_verbose bool } fn (mut ctx Context) println(s string) { if ctx.target == .alternate { ctx.omode = if ctx.omode == .stderr { Target.stdout } else { Target.stderr } } if ctx.target in [.both, .stdout] || ctx.omode == .stdout { println('stdout, $s') } if ctx.target in [.both, .stderr] || ctx.omode == .stderr { eprintln('stderr, $s') } } fn do_timeout(c &Context) { mut ctx := unsafe { c } time.sleep(ctx.timeout_ms * time.millisecond) exit(ctx.exitcode) } fn main() { mut ctx := Context{} args := os.args[1..] if '-h' in args || '--help' in args { println("Usage: test_os_process [-v] [-h] [-target stderr/stdout/both/alternate] [-exitcode 0] [-timeout_ms 200] [-period_ms 50] Prints lines periodically (-period_ms), to stdout/stderr (-target). After a while (-timeout_ms), exit with (-exitcode). This program is useful for platform independent testing of child process/standart input/output control. It is used in V's `os` module tests. ") return } ctx.is_verbose = '-v' in args ctx.target = s2target(cmdline.option(args, '-target', 'both')) ctx.exitcode = cmdline.option(args, '-exitcode', '0').int() ctx.timeout_ms = cmdline.option(args, '-timeout_ms', '200').int() ctx.period_ms = cmdline.option(args, '-period_ms', '50').int() if ctx.target == .alternate { ctx.omode = .stdout } if ctx.is_verbose { eprintln('> args: $args | context: $ctx') } spawn do_timeout(&ctx) for i := 1; true; i++ { ctx.println('$i') time.sleep(ctx.period_ms * time.millisecond) } time.sleep(100 * time.second) }