// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build unix

package syscall

import (
	
)

// origRlimitNofile, if not {0, 0}, is the original soft RLIMIT_NOFILE.
// When we can assume that we are bootstrapping with Go 1.19,
// this can be atomic.Pointer[Rlimit].
var origRlimitNofile atomic.Value // of Rlimit

// Some systems set an artificially low soft limit on open file count, for compatibility
// with code that uses select and its hard-coded maximum file descriptor
// (limited by the size of fd_set).
//
// Go does not use select, so it should not be subject to these limits.
// On some systems the limit is 256, which is very easy to run into,
// even in simple programs like gofmt when they parallelize walking
// a file tree.
//
// After a long discussion on go.dev/issue/46279, we decided the
// best approach was for Go to raise the limit unconditionally for itself,
// and then leave old software to set the limit back as needed.
// Code that really wants Go to leave the limit alone can set the hard limit,
// which Go of course has no choice but to respect.
func () {
	var  Rlimit
	if  := Getrlimit(RLIMIT_NOFILE, &);  == nil && .Cur != .Max {
		origRlimitNofile.Store()
		.Cur = .Max
		adjustFileLimit(&)
		setrlimit(RLIMIT_NOFILE, &)
	}
}

func ( int,  *Rlimit) error {
	 := setrlimit(, )
	if  == nil &&  == RLIMIT_NOFILE {
		// Store zeroes in origRlimitNofile to tell StartProcess
		// to not adjust the rlimit in the child process.
		origRlimitNofile.Store(Rlimit{0, 0})
	}
	return 
}