Package os
import "os"
The os package provides a platform-independent interface to operating system functionality. The design is Unix-like.
Package files
dir_darwin.go dir_freebsd.go dir_linux.go dir_nacl.go env.go error.go exec.go file.go getwd.go path.go proc.go stat_darwin.go stat_freebsd.go stat_linux.go stat_nacl.go sys_darwin.go sys_freebsd.go sys_linux.go sys_nacl.go time.go types.goConstants
Options for Wait.
const (
WNOHANG = syscall.WNOHANG // Don't wait if no process has exited.
WSTOPPED = syscall.WSTOPPED // If set, status of stopped subprocesses is also reported.
WUNTRACED = WSTOPPED
WRUSAGE = 1 << 20 // Record resource usage.
)
Flags to Open wrapping those of the underlying system. Not all flags may be implemented on a given system.
const (
O_RDONLY = syscall.O_RDONLY // open the file read-only.
O_WRONLY = syscall.O_WRONLY // open the file write-only.
O_RDWR = syscall.O_RDWR // open the file read-write.
O_APPEND = syscall.O_APPEND // open the file append-only.
O_ASYNC = syscall.O_ASYNC // generate a signal when I/O is available.
O_CREAT = syscall.O_CREAT // create a new file if none exists.
O_EXCL = syscall.O_EXCL // used with O_CREAT, file must not exist
O_NOCTTY = syscall.O_NOCTTY // do not make file the controlling tty.
O_NONBLOCK = syscall.O_NONBLOCK // open in non-blocking mode.
O_NDELAY = O_NONBLOCK // synonym for O_NONBLOCK
O_SYNC = syscall.O_SYNC // open for synchronous I/O.
O_TRUNC = syscall.O_TRUNC // if possible, truncate file when opened.
O_CREATE = O_CREAT // create a new file if none exists.
)
Variables
Stdin, Stdout, and Stderr are open Files pointing to the standard input, standard output, and standard error file descriptors.
var (
Stdin = NewFile(0, "/dev/stdin")
Stdout = NewFile(1, "/dev/stdout")
Stderr = NewFile(2, "/dev/stderr")
)
var Args []string // provided by runtime
ENOENV is the Error indicating that an environment variable does not exist.
var ENOENV = NewError("no such environment variable")
var Envs []string // provided by runtime
func Chdir
func Chdir(dir string) Error
Chdir changes the current working directory to the named directory.
func Chmod
func Chmod(name string, mode int) Error
Chmod changes the mode of the named file to mode. If the file is a symbolic link, it changes the mode of the link's target.
func Chown
func Chown(name string, uid, gid int) Error
Chown changes the numeric uid and gid of the named file. If the file is a symbolic link, it changes the uid and gid of the link's target.
func Clearenv
func Clearenv()
Clearenv deletes all environment variables.
func Environ
func Environ() []string
Environ returns an array of strings representing the environment, in the form "key=value".
func Exec
func Exec(argv0 string, argv []string, envv []string) Error
Exec replaces the current process with an execution of the program named by argv0, with arguments argv and environment envv. If successful, Exec never returns. If it fails, it returns an Error. ForkExec is almost always a better way to execute a program.
func Exit
func Exit(code int)
Exit causes the current program to exit with the given status code. Conventionally, code zero indicates success, non-zero an error.
func ForkExec
func ForkExec(argv0 string, argv []string, envv []string, dir string, fd []*File) (pid int, err Error)
ForkExec forks the current process and invokes Exec with the file, arguments, and environment specified by argv0, argv, and envv. It returns the process id of the forked process and an Error, if any. The fd array specifies the file descriptors to be set up in the new process: fd[0] will be Unix file descriptor 0 (standard input), fd[1] descriptor 1, and so on. A nil entry will cause the child to have no open file descriptor with that index. If dir is not empty, the child chdirs into the directory before execing the program.
func Getegid
func Getegid() int
Getegid returns the numeric effective group id of the caller.
func Getenv
func Getenv(key string) string
Getenv retrieves the value of the environment variable named by the key. It returns the value, which will be empty if the variable is not present.
func Getenverror
func Getenverror(key string) (value string, err Error)
Getenverror retrieves the value of the environment variable named by the key. It returns the value and an error, if any.
func Geteuid
func Geteuid() int
Geteuid returns the numeric effective user id of the caller.
func Getgid
func Getgid() int
Getgid returns the numeric group id of the caller.
func Getgroups
func Getgroups() ([]int, Error)
Getgroups returns a list of the numeric ids of groups that the caller belongs to.
func Getpagesize
func Getpagesize() int
Getpagesize returns the underlying system's memory page size.
func Getpid
func Getpid() int
Getpid returns the process id of the caller.
func Getppid
func Getppid() int
Getppid returns the process id of the caller's parent.
func Getuid
func Getuid() int
Getuid returns the numeric user id of the caller.
func Getwd
func Getwd() (string, Error)
Getwd returns a rooted path name corresponding to the current directory. If the current directory can be reached via multiple paths (due to symbolic links), Getwd may return any one of them.
func Hostname
func Hostname() (name string, err Error)
Hostname returns the host name reported by the kernel.
func Lchown
func Lchown(name string, uid, gid int) Error
Lchown changes the numeric uid and gid of the named file. If the file is a symbolic link, it changes the uid and gid of the link itself.
func Link
func Link(oldname, newname string) Error
Link creates a hard link.
func Mkdir
func Mkdir(name string, perm int) Error
Mkdir creates a new directory with the specified name and permission bits. It returns an error, if any.
func MkdirAll
func MkdirAll(path string, perm int) Error
MkdirAll creates a directory named path, along with any necessary parents, and returns nil, or else returns an error. The permission bits perm are used for all directories that MkdirAll creates. If path is already a directory, MkdirAll does nothing and returns nil.
func Readlink
func Readlink(name string) (string, Error)
Readlink reads the contents of a symbolic link: the destination of the link. It returns the contents and an Error, if any.
func Remove
func Remove(name string) Error
Remove removes the named file or directory.
func RemoveAll
func RemoveAll(path string) Error
RemoveAll removes path and any children it contains. It removes everything it can but returns the first error it encounters. If the path does not exist, RemoveAll returns nil (no error).
func Rename
func Rename(oldname, newname string) Error
Rename renames a file.
func Setenv
func Setenv(key, value string) Error
Setenv sets the value of the environment variable named by the key. It returns an Error, if any.
func Symlink
func Symlink(oldname, newname string) Error
Symlink creates a symbolic link.
func Time
func Time() (sec int64, nsec int64, err Error)
Time returns the current time, in whole seconds and fractional nanoseconds, plus an Error if any. The current time is thus 1e9*sec+nsec, in nanoseconds. The zero of time is the Unix epoch.
func Truncate
func Truncate(name string, size int64) Error
Truncate changes the size of the named file. If the file is a symbolic link, it changes the size of the link's target.
type Dir
A Dir describes a file and is returned by Stat, Fstat, and Lstat
type Dir struct {
Dev uint64 // device number of file system holding file.
Ino uint64 // inode number.
Nlink uint64 // number of hard links.
Mode uint32 // permission and mode bits.
Uid uint32 // user id of owner.
Gid uint32 // group id of owner.
Rdev uint64 // device type for special file.
Size uint64 // length in bytes.
Blksize uint64 // size of blocks, in bytes.
Blocks uint64 // number of blocks allocated for file.
Atime_ns uint64 // access time; nanoseconds since epoch.
Mtime_ns uint64 // modified time; nanoseconds since epoch.
Ctime_ns uint64 // status change time; nanoseconds since epoch.
Name string // name of file as presented to Open.
FollowedSymlink bool // followed a symlink to get this information
}
func Lstat
func Lstat(name string) (dir *Dir, err Error)
Lstat returns the Dir structure describing the named file and an error, if any. If the file is a symbolic link, the returned Dir describes the symbolic link. Lstat makes no attempt to follow the link.
func Stat
func Stat(name string) (dir *Dir, err Error)
Stat returns a Dir structure describing the named file and an error, if any. If name names a valid symbolic link, the returned Dir describes the file pointed at by the link and has dir.FollowedSymlink set to true. If name names an invalid symbolic link, the returned Dir describes the link itself and has dir.FollowedSymlink set to false.
func (*Dir) IsBlock
func (dir *Dir) IsBlock() bool
IsBlock reports whether the Dir describes a block special file.
func (*Dir) IsChar
func (dir *Dir) IsChar() bool
IsChar reports whether the Dir describes a character special file.
func (*Dir) IsDirectory
func (dir *Dir) IsDirectory() bool
IsDirectory reports whether the Dir describes a directory.
func (*Dir) IsFifo
func (dir *Dir) IsFifo() bool
IsFifo reports whether the Dir describes a FIFO file.
func (*Dir) IsRegular
func (dir *Dir) IsRegular() bool
IsRegular reports whether the Dir describes a regular file.
func (*Dir) IsSocket
func (dir *Dir) IsSocket() bool
IsSocket reports whether the Dir describes a socket.
func (*Dir) IsSymlink
func (dir *Dir) IsSymlink() bool
IsSymlink reports whether the Dir describes a symbolic link.
func (*Dir) Permission
func (dir *Dir) Permission() int
Permission returns the file permission bits.
type Errno
Errno is the Unix error number. Names such as EINVAL are simple wrappers to convert the error number into an Error.
type Errno int64
func (Errno) String
func (e Errno) String() string
type Error
An Error can represent any printable error condition.
type Error interface {
String() string
}
Commonly known Unix errors.
var (
EPERM Error = Errno(syscall.EPERM)
ENOENT Error = Errno(syscall.ENOENT)
ESRCH Error = Errno(syscall.ESRCH)
EINTR Error = Errno(syscall.EINTR)
EIO Error = Errno(syscall.EIO)
ENXIO Error = Errno(syscall.ENXIO)
E2BIG Error = Errno(syscall.E2BIG)
ENOEXEC Error = Errno(syscall.ENOEXEC)
EBADF Error = Errno(syscall.EBADF)
ECHILD Error = Errno(syscall.ECHILD)
EDEADLK Error = Errno(syscall.EDEADLK)
ENOMEM Error = Errno(syscall.ENOMEM)
EACCES Error = Errno(syscall.EACCES)
EFAULT Error = Errno(syscall.EFAULT)
EBUSY Error = Errno(syscall.EBUSY)
EEXIST Error = Errno(syscall.EEXIST)
EXDEV Error = Errno(syscall.EXDEV)
ENODEV Error = Errno(syscall.ENODEV)
ENOTDIR Error = Errno(syscall.ENOTDIR)
EISDIR Error = Errno(syscall.EISDIR)
EINVAL Error = Errno(syscall.EINVAL)
ENFILE Error = Errno(syscall.ENFILE)
EMFILE Error = Errno(syscall.EMFILE)
ENOTTY Error = Errno(syscall.ENOTTY)
EFBIG Error = Errno(syscall.EFBIG)
ENOSPC Error = Errno(syscall.ENOSPC)
ESPIPE Error = Errno(syscall.ESPIPE)
EROFS Error = Errno(syscall.EROFS)
EMLINK Error = Errno(syscall.EMLINK)
EPIPE Error = Errno(syscall.EPIPE)
EAGAIN Error = Errno(syscall.EAGAIN)
EDOM Error = Errno(syscall.EDOM)
ERANGE Error = Errno(syscall.ERANGE)
EADDRINUSE Error = Errno(syscall.EADDRINUSE)
ECONNREFUSED Error = Errno(syscall.ECONNREFUSED)
ENAMETOOLONG Error = Errno(syscall.ENAMETOOLONG)
EAFNOSUPPORT Error = Errno(syscall.EAFNOSUPPORT)
)
EOF is the Error returned by Read when no more input is available. Functions should return EOF only to signal a graceful end of input. If the EOF occurs unexpectedly in a structured data stream, the appropriate error is either io.ErrUnexpectedEOF or some other error giving more detail.
var EOF Error = eofError(0)
func NewError
func NewError(s string) Error
NewError converts s to an ErrorString, which satisfies the Error interface.
func NewSyscallError
func NewSyscallError(syscall string, errno int) Error
NewSyscallError returns, as an Error, a new SyscallError with the given system call name and error number. As a convenience, if errno is 0, NewSyscallError returns nil.
type ErrorString
A helper type that can be embedded or wrapped to simplify satisfying Error.
type ErrorString string
func (ErrorString) String
func (e ErrorString) String() string
type File
File represents an open file descriptor.
type File struct {
// contains unexported fields
}
func NewFile
func NewFile(fd int, name string) *File
NewFile returns a new File with the given file descriptor and name.
func Open
func Open(name string, flag int, perm int) (file *File, err Error)
Open opens the named file with specified flag (O_RDONLY etc.) and perm, (0666 etc.) if applicable. If successful, methods on the returned File can be used for I/O. It returns the File and an Error, if any.
func Pipe
func Pipe() (r *File, w *File, err Error)
Pipe returns a connected pair of Files; reads from r return bytes written to w. It returns the files and an Error, if any.
func (*File) Chdir
func (f *File) Chdir() Error
Chdir changes the current working directory to the file, which must be a directory.
func (*File) Chmod
func (f *File) Chmod(mode int) Error
Chmod changes the mode of the file to mode.
func (*File) Chown
func (f *File) Chown(uid, gid int) Error
Chown changes the numeric uid and gid of the named file.
func (*File) Close
func (file *File) Close() Error
Close closes the File, rendering it unusable for I/O. It returns an Error, if any.
func (*File) Fd
func (file *File) Fd() int
Fd returns the integer Unix file descriptor referencing the open file.
func (*File) Name
func (file *File) Name() string
Name returns the name of the file as presented to Open.
func (*File) Read
func (file *File) Read(b []byte) (n int, err Error)
Read reads up to len(b) bytes from the File. It returns the number of bytes read and an Error, if any. EOF is signaled by a zero count with err set to EOF.
func (*File) ReadAt
func (file *File) ReadAt(b []byte, off int64) (n int, err Error)
ReadAt reads len(b) bytes from the File starting at byte offset off. It returns the number of bytes read and the Error, if any. EOF is signaled by a zero count with err set to EOF. ReadAt always returns a non-nil Error when n != len(b).
func (*File) Readdir
func (file *File) Readdir(count int) (dirs []Dir, err Error)
Readdir reads the contents of the directory associated with file and returns an array of up to count Dir structures, as would be returned by Stat, in directory order. Subsequent calls on the same file will yield further Dirs. A negative count means to read until EOF. Readdir returns the array and an Error, if any.
func (*File) Readdirnames
func (file *File) Readdirnames(count int) (names []string, err Error)
func (*File) Seek
func (file *File) Seek(offset int64, whence int) (ret int64, err Error)
Seek sets the offset for the next Read or Write on file to offset, interpreted according to whence: 0 means relative to the origin of the file, 1 means relative to the current offset, and 2 means relative to the end. It returns the new offset and an Error, if any.
func (*File) Stat
func (file *File) Stat() (dir *Dir, err Error)
Stat returns the Dir structure describing file. It returns the Dir and an error, if any.
func (*File) Truncate
func (f *File) Truncate(size int64) Error
Truncate changes the size of the file. It does not change the I/O offset.
func (*File) Write
func (file *File) Write(b []byte) (n int, err Error)
Write writes len(b) bytes to the File. It returns the number of bytes written and an Error, if any. Write returns a non-nil Error when n != len(b).
func (*File) WriteAt
func (file *File) WriteAt(b []byte, off int64) (n int, err Error)
WriteAt writes len(b) bytes to the File starting at byte offset off. It returns the number of bytes written and an Error, if any. WriteAt returns a non-nil Error when n != len(b).
func (*File) WriteString
func (file *File) WriteString(s string) (ret int, err Error)
WriteString is like Write, but writes the contents of string s rather than an array of bytes.
type LinkError
LinkError records an error during a link or symlink or rename system call and the paths that caused it.
type LinkError struct {
Op string
Old string
New string
Error Error
}
func (*LinkError) String
func (e *LinkError) String() string
type PathError
PathError records an error and the operation and file path that caused it.
type PathError struct {
Op string
Path string
Error Error
}
func (*PathError) String
func (e *PathError) String() string
type SyscallError
SyscallError records an error from a specific system call.
type SyscallError struct {
Syscall string
Errno Errno
}
func (*SyscallError) String
func (e *SyscallError) String() string
type Waitmsg
Waitmsg stores the information about an exited process as reported by Wait.
type Waitmsg struct {
Pid int // The process's id.
syscall.WaitStatus // System-dependent status info.
Rusage *syscall.Rusage // System-dependent resource usage info.
}
func Wait
func Wait(pid int, options int) (w *Waitmsg, err Error)
Wait waits for process pid to exit or stop, and then returns a Waitmsg describing its status and an Error, if any. The options (WNOHANG etc.) affect the behavior of the Wait call.
func (Waitmsg) String
func (w Waitmsg) String() string
Subdirectories
| Name | Synopsis | |
|---|---|---|
| .. | ||
| signal | Package signal implements operating system-independent signal handling. |