os

package
v0.9.0 Latest Latest
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 Go to latest Published: Jul 7, 2024 License: Apache-2.0 Imports: 9 Imported by: 0

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Index

Constants

View Source 
const (
	// Exactly one of O_RDONLY, O_WRONLY, or O_RDWR must be specified.
	O_RDONLY int = syscall.O_RDONLY // open the file read-only.
	O_WRONLY int = syscall.O_WRONLY // open the file write-only.
	O_RDWR   int = syscall.O_RDWR   // open the file read-write.
	// The remaining values may be or'ed in to control behavior.
	O_APPEND int = syscall.O_APPEND // append data to the file when writing.
	O_CREATE int = syscall.O_CREAT  // create a new file if none exists.
	O_EXCL   int = syscall.O_EXCL   // used with O_CREATE, file must not exist.
	O_SYNC   int = syscall.O_SYNC   // open for synchronous I/O.
	O_TRUNC  int = syscall.O_TRUNC  // truncate regular writable file when opened.
)

Flags to OpenFile wrapping those of the underlying system. Not all flags may be implemented on a given system.

View Source 
const (
	SEEK_SET int = 0 // seek relative to the origin of the file
	SEEK_CUR int = 1 // seek relative to the current offset
	SEEK_END int = 2 // seek relative to the end
)

Seek whence values.

Deprecated: Use io.SeekStart, io.SeekCurrent, and io.SeekEnd.

View Source 
const (
	// The single letters are the abbreviations
	// used by the String method's formatting.
	ModeDir        = fs.ModeDir        // d: is a directory
	ModeAppend     = fs.ModeAppend     // a: append-only
	ModeExclusive  = fs.ModeExclusive  // l: exclusive use
	ModeTemporary  = fs.ModeTemporary  // T: temporary file; Plan 9 only
	ModeSymlink    = fs.ModeSymlink    // L: symbolic link
	ModeDevice     = fs.ModeDevice     // D: device file
	ModeNamedPipe  = fs.ModeNamedPipe  // p: named pipe (FIFO)
	ModeSocket     = fs.ModeSocket     // S: Unix domain socket
	ModeSetuid     = fs.ModeSetuid     // u: setuid
	ModeSetgid     = fs.ModeSetgid     // g: setgid
	ModeCharDevice = fs.ModeCharDevice // c: Unix character device, when ModeDevice is set
	ModeSticky     = fs.ModeSticky     // t: sticky
	ModeIrregular  = fs.ModeIrregular  // ?: non-regular file; nothing else is known about this file

	// Mask for the type bits. For regular files, none will be set.
	ModeType = fs.ModeType

	ModePerm = fs.ModePerm // Unix permission bits, 0o777
)

The defined file mode bits are the most significant bits of the FileMode. The nine least-significant bits are the standard Unix rwxrwxrwx permissions. The values of these bits should be considered part of the public API and may be used in wire protocols or disk representations: they must not be changed, although new bits might be added.

View Source 
const (
	LLGoPackage = true
)

Variables

View Source 
var (
	// ErrInvalid indicates an invalid argument.
	// Methods on File will return this error when the receiver is nil.
	ErrInvalid = fs.ErrInvalid // "invalid argument"

	ErrPermission = fs.ErrPermission // "permission denied"
	ErrExist      = fs.ErrExist      // "file already exists"
	ErrNotExist   = fs.ErrNotExist   // "file does not exist"
	ErrClosed     = fs.ErrClosed     // "file already closed"

)

Portable analogs of some common system call errors.

Errors returned from this package may be tested against these errors with errors.Is.

View Source 
var (
	Stdin  = NewFile(uintptr(syscall.Stdin), "/dev/stdin")
	Stdout = NewFile(uintptr(syscall.Stdout), "/dev/stdout")
	Stderr = NewFile(uintptr(syscall.Stderr), "/dev/stderr")
)

Stdin, Stdout, and Stderr are open Files pointing to the standard input, standard output, and standard error file descriptors.

Note that the Go runtime writes to standard error for panics and crashes; closing Stderr may cause those messages to go elsewhere, perhaps to a file opened later.

Functions

func Chdir 

func Chdir(dir string) error

func Chmod 

func Chmod(name string, mode FileMode) error

func Chown 

func Chown(name string, uid, gid int) error

func Clearenv 

func Clearenv()

func Exit 

func Exit(code int)

func Getegid 

func Getegid() int

func Getenv 

func Getenv(key string) string

func Geteuid 

func Geteuid() int

func Getgid 

func Getgid() int

func Getpagesize added in v0.8.10 

func Getpagesize() int

Getpagesize returns the underlying system's memory page size.

func Getpid 

func Getpid() int

func Getppid 

func Getppid() int

func Getuid 

func Getuid() int

func Getwd 

func Getwd() (dir string, err error)

func IsExist added in v0.8.10 

func IsExist(err error) bool

IsExist returns a boolean indicating whether the error is known to report that a file or directory already exists. It is satisfied by ErrExist as well as some syscall errors.

This function predates errors.Is. It only supports errors returned by the os package. New code should use errors.Is(err, fs.ErrExist).

func IsNotExist added in v0.8.10 

func IsNotExist(err error) bool

IsNotExist returns a boolean indicating whether the error is known to report that a file or directory does not exist. It is satisfied by ErrNotExist as well as some syscall errors.

This function predates errors.Is. It only supports errors returned by the os package. New code should use errors.Is(err, fs.ErrNotExist).

func IsPermission added in v0.8.10 

func IsPermission(err error) bool

IsPermission returns a boolean indicating whether the error is known to report that permission is denied. It is satisfied by ErrPermission as well as some syscall errors.

This function predates errors.Is. It only supports errors returned by the os package. New code should use errors.Is(err, fs.ErrPermission).

func IsTimeout added in v0.8.10 

func IsTimeout(err error) bool

IsTimeout returns a boolean indicating whether the error is known to report that a timeout occurred.

This function predates errors.Is, and the notion of whether an error indicates a timeout can be ambiguous. For example, the Unix error EWOULDBLOCK sometimes indicates a timeout and sometimes does not. New code should use errors.Is with a value appropriate to the call returning the error, such as os.ErrDeadlineExceeded.

func Lchown 

func Lchown(name string, uid, gid int) error
func Link(oldname, newname string) error

func Mkdir 

func Mkdir(name string, perm FileMode) error

func NewSyscallError 

func NewSyscallError(syscall string, err error) error

NewSyscallError returns, as an error, a new SyscallError with the given system call name and error details. As a convenience, if err is nil, NewSyscallError returns nil. 

func Readlink(name string) (string, error)

func Remove 

func Remove(name string) error

func Rename 

func Rename(oldpath, newpath string) error

func SameFile added in v0.8.10 

func SameFile(fi1, fi2 FileInfo) bool

SameFile reports whether fi1 and fi2 describe the same file. For example, on Unix this means that the device and inode fields of the two underlying structures are identical; on other systems the decision may be based on the path names. SameFile only applies to results returned by this package's Stat. It returns false in other cases.

func Setenv 

func Setenv(key, value string) error
func Symlink(oldname, newname string) error

func Truncate 

func Truncate(name string, size int64) error

func Unsetenv 

func Unsetenv(key string) error

func UserCacheDir added in v0.8.10 

func UserCacheDir() (string, error)

UserCacheDir returns the default root directory to use for user-specific cached data. Users should create their own application-specific subdirectory within this one and use that.

On Unix systems, it returns $XDG_CACHE_HOME as specified by https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html if non-empty, else $HOME/.cache. On Darwin, it returns $HOME/Library/Caches. On Windows, it returns %LocalAppData%. On Plan 9, it returns $home/lib/cache.

If the location cannot be determined (for example, $HOME is not defined), then it will return an error.

func UserConfigDir added in v0.8.10 

func UserConfigDir() (string, error)

UserConfigDir returns the default root directory to use for user-specific configuration data. Users should create their own application-specific subdirectory within this one and use that.

On Unix systems, it returns $XDG_CONFIG_HOME as specified by https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html if non-empty, else $HOME/.config. On Darwin, it returns $HOME/Library/Application Support. On Windows, it returns %AppData%. On Plan 9, it returns $home/lib.

If the location cannot be determined (for example, $HOME is not defined), then it will return an error.

func UserHomeDir added in v0.8.10 

func UserHomeDir() (string, error)

UserHomeDir returns the current user's home directory.

On Unix, including macOS, it returns the $HOME environment variable. On Windows, it returns %USERPROFILE%. On Plan 9, it returns the $home environment variable.

If the expected variable is not set in the environment, UserHomeDir returns either a platform-specific default value or a non-nil error.

Types

type File added in v0.8.10 

type File struct {
	// contains filtered or unexported fields
}

File represents an open file descriptor.

func NewFile added in v0.8.10 

func NewFile(fd uintptr, name string) *File

NewFile returns a new File with the given file descriptor and name. The returned value will be nil if fd is not a valid file descriptor. On Unix systems, if the file descriptor is in non-blocking mode, NewFile will attempt to return a pollable File (one for which the SetDeadline methods work).

After passing it to NewFile, fd may become invalid under the same conditions described in the comments of the Fd method, and the same constraints apply.

func (*File) Chdir added in v0.8.10 

func (f *File) Chdir() error

Chdir changes the current working directory to the file, which must be a directory. If there is an error, it will be of type *PathError.

func (*File) Chmod added in v0.8.10 

func (f *File) Chmod(mode FileMode) error

Chmod changes the mode of the file to mode. If there is an error, it will be of type *PathError.

func (*File) Chown added in v0.8.10 

func (f *File) Chown(uid, gid int) error

Chown changes the numeric uid and gid of the named file. If there is an error, it will be of type *PathError.

On Windows, it always returns the syscall.EWINDOWS error, wrapped in *PathError.

func (*File) Close added in v0.8.10 

func (f *File) Close() error

Close closes the File, rendering it unusable for I/O. On files that support SetDeadline, any pending I/O operations will be canceled and return immediately with an ErrClosed error. Close will return an error if it has already been called.

func (*File) Name added in v0.8.10 

func (f *File) Name() string

Name returns the name of the file as presented to Open.

func (*File) Read added in v0.8.10 

func (f *File) Read(b []byte) (n int, err error)

Read reads up to len(b) bytes from the File and stores them in b. It returns the number of bytes read and any error encountered. At end of file, Read returns 0, io.EOF.

func (*File) ReadAt added in v0.8.10 

func (f *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. ReadAt always returns a non-nil error when n < len(b). At end of file, that error is io.EOF.

func (*File) ReadFrom added in v0.8.10 

func (f *File) ReadFrom(r io.Reader) (n int64, err error)

ReadFrom implements io.ReaderFrom.

func (*File) Seek added in v0.8.10 

func (f *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. The behavior of Seek on a file opened with O_APPEND is not specified.

func (*File) SetDeadline added in v0.8.10 

func (f *File) SetDeadline(t time.Time) error

SetDeadline sets the read and write deadlines for a File. It is equivalent to calling both SetReadDeadline and SetWriteDeadline.

Only some kinds of files support setting a deadline. Calls to SetDeadline for files that do not support deadlines will return ErrNoDeadline. On most systems ordinary files do not support deadlines, but pipes do.

A deadline is an absolute time after which I/O operations fail with an error instead of blocking. The deadline applies to all future and pending I/O, not just the immediately following call to Read or Write. After a deadline has been exceeded, the connection can be refreshed by setting a deadline in the future.

If the deadline is exceeded a call to Read or Write or to other I/O methods will return an error that wraps ErrDeadlineExceeded. This can be tested using errors.Is(err, os.ErrDeadlineExceeded). That error implements the Timeout method, and calling the Timeout method will return true, but there are other possible errors for which the Timeout will return true even if the deadline has not been exceeded.

An idle timeout can be implemented by repeatedly extending the deadline after successful Read or Write calls.

A zero value for t means I/O operations will not time out.

func (*File) SetReadDeadline added in v0.8.10 

func (f *File) SetReadDeadline(t time.Time) error

SetReadDeadline sets the deadline for future Read calls and any currently-blocked Read call. A zero value for t means Read will not time out. Not all files support setting deadlines; see SetDeadline.

func (*File) SetWriteDeadline added in v0.8.10 

func (f *File) SetWriteDeadline(t time.Time) error

SetWriteDeadline sets the deadline for any future Write calls and any currently-blocked Write call. Even if Write times out, it may return n > 0, indicating that some of the data was successfully written. A zero value for t means Write will not time out. Not all files support setting deadlines; see SetDeadline.

func (*File) Sync added in v0.8.10 

func (f *File) Sync() error

Sync commits the current contents of the file to stable storage. Typically, this means flushing the file system's in-memory copy of recently written data to disk.

func (*File) SyscallConn added in v0.8.10 

func (f *File) SyscallConn() (syscall.RawConn, error)

SyscallConn returns a raw file. This implements the syscall.Conn interface.

func (*File) Truncate added in v0.8.10 

func (f *File) Truncate(size int64) error

Truncate changes the size of the file. It does not change the I/O offset. If there is an error, it will be of type *PathError.

func (*File) Write added in v0.8.10 

func (f *File) Write(b []byte) (n int, err error)

Write writes len(b) bytes from b 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 added in v0.8.10 

func (f *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).

If file was opened with the O_APPEND flag, WriteAt returns an error.

func (*File) WriteString added in v0.8.10 

func (f *File) WriteString(s string) (n int, err error)

WriteString is like Write, but writes the contents of string s rather than a slice of bytes.

type FileInfo added in v0.8.10 

type FileInfo = fs.FileInfo

A FileInfo describes a file and is returned by Stat and Lstat.

type FileMode 

type FileMode = fs.FileMode

A FileMode represents a file's mode and permission bits. The bits have the same definition on all systems, so that information about files can be moved from one system to another portably. Not all bits apply to all systems. The only required bit is ModeDir for directories.

type LinkError 

type LinkError struct {
	Op  string
	Old string
	New string
	Err error
}

LinkError records an error during a link or symlink or rename system call and the paths that caused it.

func (*LinkError) Error 

func (e *LinkError) Error() string

func (*LinkError) Unwrap 

func (e *LinkError) Unwrap() error

type PathError 

type PathError = fs.PathError

PathError records an error and the operation and file path that caused it.

type SyscallError 

type SyscallError struct {
	Syscall string
	Err     error
}

SyscallError records an error from a specific system call.

func (*SyscallError) Error 

func (e *SyscallError) Error() string

func (*SyscallError) Timeout 

func (e *SyscallError) Timeout() bool

Timeout reports whether this error represents a timeout.

func (*SyscallError) Unwrap 

func (e *SyscallError) Unwrap() error

Source Files

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