| // Copyright 2018 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 dragonfly || freebsd || linux || netbsd || openbsd |
| |
| package unix |
| |
| import "syscall" |
| |
| // FcntlSyscall is the number for the fcntl system call. This is |
| // usually SYS_FCNTL, but can be overridden to SYS_FCNTL64. |
| var FcntlSyscall uintptr = syscall.SYS_FCNTL |
| |
| func IsNonblock(fd int) (nonblocking bool, err error) { |
| flag, _, e1 := syscall.Syscall(FcntlSyscall, uintptr(fd), uintptr(syscall.F_GETFL), 0) |
| if e1 != 0 { |
| return false, e1 |
| } |
| return flag&syscall.O_NONBLOCK != 0, nil |
| } |
