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fcntl.go (1075B)

      1 // Copyright 2014 The Go Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 //go:build dragonfly || freebsd || linux || netbsd
      6 
      7 package unix
      8 
      9 import "unsafe"
     10 
     11 // fcntl64Syscall is usually SYS_FCNTL, but is overridden on 32-bit Linux
     12 // systems by fcntl_linux_32bit.go to be SYS_FCNTL64.
     13 var fcntl64Syscall uintptr = SYS_FCNTL
     14 
     15 func fcntl(fd int, cmd, arg int) (int, error) {
     16 	valptr, _, errno := Syscall(fcntl64Syscall, uintptr(fd), uintptr(cmd), uintptr(arg))
     17 	var err error
     18 	if errno != 0 {
     19 		err = errno
     20 	}
     21 	return int(valptr), err
     22 }
     23 
     24 // FcntlInt performs a fcntl syscall on fd with the provided command and argument.
     25 func FcntlInt(fd uintptr, cmd, arg int) (int, error) {
     26 	return fcntl(int(fd), cmd, arg)
     27 }
     28 
     29 // FcntlFlock performs a fcntl syscall for the F_GETLK, F_SETLK or F_SETLKW command.
     30 func FcntlFlock(fd uintptr, cmd int, lk *Flock_t) error {
     31 	_, _, errno := Syscall(fcntl64Syscall, fd, uintptr(cmd), uintptr(unsafe.Pointer(lk)))
     32 	if errno == 0 {
     33 		return nil
     34 	}
     35 	return errno
     36 }