libgo/go/os/doc.go

   1 // Copyright 2012 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 os
   6
   7 import "time"
   8
   9 // FindProcess looks for a running process by its pid.
  10 // The Process it returns can be used to obtain information
  11 // about the underlying operating system process.
  12 func FindProcess(pid int) (p *Process, err error) {
  13         return findProcess(pid)
  14 }
  15
  16 // StartProcess starts a new process with the program, arguments and attributes
  17 // specified by name, argv and attr.
  18 //
  19 // StartProcess is a low-level interface. The os/exec package provides
  20 // higher-level interfaces.
  21 //
  22 // If there is an error, it will be of type *PathError.
  23 func StartProcess(name string, argv []string, attr *ProcAttr) (*Process, error) {
  24         return startProcess(name, argv, attr)
  25 }
  26
  27 // Release releases any resources associated with the Process p,
  28 // rendering it unusable in the future.
  29 // Release only needs to be called if Wait is not.
  30 func (p *Process) Release() error {
  31         return p.release()
  32 }
  33
  34 // Kill causes the Process to exit immediately.
  35 func (p *Process) Kill() error {
  36         return p.kill()
  37 }
  38
  39 // Wait waits for the Process to exit, and then returns a
  40 // ProcessState describing its status and an error, if any.
  41 // Wait releases any resources associated with the Process.
  42 func (p *Process) Wait() (*ProcessState, error) {
  43         return p.wait()
  44 }
  45
  46 // Signal sends a signal to the Process.
  47 func (p *Process) Signal(sig Signal) error {
  48         return p.signal(sig)
  49 }
  50
  51 // UserTime returns the user CPU time of the exited process and its children.
  52 func (p *ProcessState) UserTime() time.Duration {
  53         return p.userTime()
  54 }
  55
  56 // SystemTime returns the system CPU time of the exited process and its children.
  57 func (p *ProcessState) SystemTime() time.Duration {
  58         return p.systemTime()
  59 }
  60
  61 // Exited reports whether the program has exited.
  62 func (p *ProcessState) Exited() bool {
  63         return p.exited()
  64 }
  65
  66 // Success reports whether the program exited successfully,
  67 // such as with exit status 0 on Unix.
  68 func (p *ProcessState) Success() bool {
  69         return p.success()
  70 }
  71
  72 // Sys returns system-dependent exit information about
  73 // the process.  Convert it to the appropriate underlying
  74 // type, such as syscall.WaitStatus on Unix, to access its contents.
  75 func (p *ProcessState) Sys() interface{} {
  76         return p.sys()
  77 }
  78
  79 // SysUsage returns system-dependent resource usage information about
  80 // the exited process.  Convert it to the appropriate underlying
  81 // type, such as *syscall.Rusage on Unix, to access its contents.
  82 // (On Unix, *syscall.Rusage matches struct rusage as defined in the
  83 // getrusage(2) manual page.)
  84 func (p *ProcessState) SysUsage() interface{} {
  85         return p.sysUsage()
  86 }
  87
  88 // Hostname returns the host name reported by the kernel.
  89 func Hostname() (name string, err error) {
  90         return hostname()
  91 }
  92
  93 // Readdir reads the contents of the directory associated with file and
  94 // returns a slice of up to n FileInfo values, as would be returned
  95 // by Lstat, in directory order. Subsequent calls on the same file will yield
  96 // further FileInfos.
  97 //
  98 // If n > 0, Readdir returns at most n FileInfo structures. In this case, if
  99 // Readdir returns an empty slice, it will return a non-nil error
 100 // explaining why. At the end of a directory, the error is io.EOF.
 101 //
 102 // If n <= 0, Readdir returns all the FileInfo from the directory in
 103 // a single slice. In this case, if Readdir succeeds (reads all
 104 // the way to the end of the directory), it returns the slice and a
 105 // nil error. If it encounters an error before the end of the
 106 // directory, Readdir returns the FileInfo read until that point
 107 // and a non-nil error.
 108 func (f *File) Readdir(n int) (fi []FileInfo, err error) {
 109         if f == nil {
 110                 return nil, ErrInvalid
 111         }
 112         return f.readdir(n)
 113 }
 114
 115 // Readdirnames reads and returns a slice of names from the directory f.
 116 //
 117 // If n > 0, Readdirnames returns at most n names. In this case, if
 118 // Readdirnames returns an empty slice, it will return a non-nil error
 119 // explaining why. At the end of a directory, the error is io.EOF.
 120 //
 121 // If n <= 0, Readdirnames returns all the names from the directory in
 122 // a single slice. In this case, if Readdirnames succeeds (reads all
 123 // the way to the end of the directory), it returns the slice and a
 124 // nil error. If it encounters an error before the end of the
 125 // directory, Readdirnames returns the names read until that point and
 126 // a non-nil error.
 127 func (f *File) Readdirnames(n int) (names []string, err error) {
 128         if f == nil {
 129                 return nil, ErrInvalid
 130         }
 131         return f.readdirnames(n)
 132 }