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Package ioutil

import "io/ioutil"
Overview
Index
Examples

Overview ▾

Package ioutil implements some I/O utility functions.

Variables

Discard is an io.Writer on which all Write calls succeed without doing anything.

var Discard io.Writer = devNull(0)

func NopCloser

NopCloser returns a ReadCloser with a no-op Close method wrapping the provided Reader r.

func NopCloser(r io.Reader) io.ReadCloser

func ReadAll

ReadAll reads from r until an error or EOF and returns the data it read. A successful call returns err == nil, not err == EOF. Because ReadAll is defined to read from src until EOF, it does not treat an EOF from Read as an error to be reported.

func ReadAll(r io.Reader) ([]byte, error)

Example

Go is a general-purpose language designed with systems programming in mind.

func ReadDir

ReadDir reads the directory named by dirname and returns a list of directory entries sorted by filename.

func ReadDir(dirname string) ([]os.FileInfo, error)

Example

func ReadFile

ReadFile reads the file named by filename and returns the contents. A successful call returns err == nil, not err == EOF. Because ReadFile reads the whole file, it does not treat an EOF from Read as an error to be reported.

func ReadFile(filename string) ([]byte, error)

func TempDir

TempDir creates a new temporary directory in the directory dir with a name beginning with prefix and returns the path of the new directory. If dir is the empty string, TempDir uses the default directory for temporary files (see os.TempDir). Multiple programs calling TempDir simultaneously will not choose the same directory. It is the caller's responsibility to remove the directory when no longer needed.

func TempDir(dir, prefix string) (name string, err error)

Example

func TempFile

TempFile creates a new temporary file in the directory dir with a name beginning with prefix, opens the file for reading and writing, and returns the resulting *os.File. If dir is the empty string, TempFile uses the default directory for temporary files (see os.TempDir). Multiple programs calling TempFile simultaneously will not choose the same file. The caller can use f.Name() to find the pathname of the file. It is the caller's responsibility to remove the file when no longer needed.

func TempFile(dir, prefix string) (f *os.File, err error)

Example

func WriteFile

WriteFile writes data to a file named by filename. If the file does not exist, WriteFile creates it with permissions perm; otherwise WriteFile truncates it before writing.

func WriteFile(filename string, data []byte, perm os.FileMode) error