libgo/go/syscall/syscall.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 contains an interface to the low-level operating system
   6 // primitives.  The details vary depending on the underlying system, and
   7 // by default, godoc will display the syscall documentation for the current
   8 // system.  If you want godoc to display syscall documentation for another
   9 // system, set $GOOS and $GOARCH to the desired system.  For example, if
  10 // you want to view documentation for freebsd/arm on linux/amd64, set $GOOS
  11 // to freebsd and $GOARCH to arm.
  12 // The primary use of syscall is inside other packages that provide a more
  13 // portable interface to the system, such as "os", "time" and "net".  Use
  14 // those packages rather than this one if you can.
  15 // For details of the functions and data types in this package consult
  16 // the manuals for the appropriate operating system.
  17 // These calls return err == nil to indicate success; otherwise
  18 // err is an operating system error describing the failure.
  19 // On most systems, that error has type syscall.Errno.
  20 package syscall
  21
  22 import "unsafe"
  23
  24 // StringByteSlice is deprecated. Use ByteSliceFromString instead.
  25 // If s contains a NUL byte this function panics instead of
  26 // returning an error.
  27 func StringByteSlice(s string) []byte {
  28         a, err := ByteSliceFromString(s)
  29         if err != nil {
  30                 panic("syscall: string with NUL passed to StringByteSlice")
  31         }
  32         return a
  33 }
  34
  35 // ByteSliceFromString returns a NUL-terminated slice of bytes
  36 // containing the text of s. If s contains a NUL byte at any
  37 // location, it returns (nil, EINVAL).
  38 func ByteSliceFromString(s string) ([]byte, error) {
  39         for i := 0; i < len(s); i++ {
  40                 if s[i] == 0 {
  41                         return nil, EINVAL
  42                 }
  43         }
  44         a := make([]byte, len(s)+1)
  45         copy(a, s)
  46         return a, nil
  47 }
  48
  49 // StringBytePtr is deprecated. Use BytePtrFromString instead.
  50 // If s contains a NUL byte this function panics instead of
  51 // returning an error.
  52 func StringBytePtr(s string) *byte { return &StringByteSlice(s)[0] }
  53
  54 // BytePtrFromString returns a pointer to a NUL-terminated array of
  55 // bytes containing the text of s. If s contains a NUL byte at any
  56 // location, it returns (nil, EINVAL).
  57 func BytePtrFromString(s string) (*byte, error) {
  58         a, err := ByteSliceFromString(s)
  59         if err != nil {
  60                 return nil, err
  61         }
  62         return &a[0], nil
  63 }
  64
  65 // Single-word zero for use when we need a valid pointer to 0 bytes.
  66 // See mksyscall.pl.
  67 var _zero uintptr
  68
  69 var dummy *byte
  70
  71 const sizeofPtr uintptr = uintptr(unsafe.Sizeof(dummy))
  72
  73 func (ts *Timespec) Unix() (sec int64, nsec int64) {
  74         return int64(ts.Sec), int64(ts.Nsec)
  75 }
  76
  77 func (tv *Timeval) Unix() (sec int64, nsec int64) {
  78         return int64(tv.Sec), int64(tv.Usec) * 1000
  79 }
  80
  81 func (ts *Timespec) Nano() int64 {
  82         return int64(ts.Sec)*1e9 + int64(ts.Nsec)
  83 }
  84
  85 func (tv *Timeval) Nano() int64 {
  86         return int64(tv.Sec)*1e9 + int64(tv.Usec)*1000
  87 }