libgo/go/syscall/syscall_errno.go

   1 // Copyright 2009 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 package syscall
   6
   7 import "internal/oserror"
   8
   9 // An Errno is an unsigned number describing an error condition.
  10 // It implements the error interface.  The zero Errno is by convention
  11 // a non-error, so code to convert from Errno to error should use:
  12 //      err = nil
  13 //      if errno != 0 {
  14 //              err = errno
  15 //      }
  16 //
  17 // Errno values can be tested against error values from the os package
  18 // using errors.Is. For example:
  19 //
  20 //      _, _, err := syscall.Syscall(...)
  21 //      if errors.Is(err, os.ErrNotExist) ...
  22 type Errno uintptr
  23
  24 func (e Errno) Error() string {
  25         return Errstr(int(e))
  26 }
  27
  28 func (e Errno) Is(target error) bool {
  29         switch target {
  30         case oserror.ErrPermission:
  31                 return e == EACCES || e == EPERM
  32         case oserror.ErrExist:
  33                 return e == EEXIST || e == ENOTEMPTY
  34         case oserror.ErrNotExist:
  35                 return e == ENOENT
  36         }
  37         return false
  38 }
  39
  40 func (e Errno) Temporary() bool {
  41         return e == EINTR || e == EMFILE || e == ENFILE || e.Timeout()
  42 }
  43
  44 func (e Errno) Timeout() bool {
  45         return e == EAGAIN || e == EWOULDBLOCK || e == ETIMEDOUT
  46 }