File input/output - cppreference.com

header provides generic file operation support and supplies functions with narrow character input/output capabilities.

The

header supplies functions with wide character input/output capabilities.

I/O streams are denoted by objects of type

FILE

that can only be accessed and manipulated through pointers of type FILE*. Each stream is associated with an external physical device (file, standard input stream, printer, serial port, etc).

Types

object type, capable of holding all information needed to control a C I/O stream
(typedef)

non-array complete object type, capable of uniquely specifying a position and multibyte parser state in a file
(typedef)

Predefined standard streams

expression of type FILE* associated with the input stream
expression of type FILE* associated with the output stream
expression of type FILE* associated with the error output stream
(macro constant)

Functions

File access Defined in header

fopenfopen_s

(C11)

opens a file
(function)

freopenfreopen_s

(C11)

open an existing stream with a different name
(function)

fclose

closes a file
(function)

fflush

synchronizes an output stream with the actual file
(function)

setbuf

sets the buffer for a file stream
(function)

setvbuf

sets the buffer and its size for a file stream
(function)

Defined in header

fwide

(C95)

switches a file stream between wide character I/O and narrow character I/O
(function)

Direct input/output Defined in header

fread

reads from a file
(function)

fwrite

writes to a file
(function)

Unformatted input/output Narrow characterDefined in header

fgetcgetc

gets a character from a file stream
(function)

fgets

gets a character string from a file stream
(function)

fputcputc

writes a character to a file stream
(function)

fputs

writes a character string to a file stream
(function)

getchar

reads a character from

(function)

getsgets_s

(removed in C11)(C11)

reads a character string from

(function)

putchar

writes a character to

(function)

puts

writes a character string to

(function)

ungetc

puts a character back into a file stream
(function)

Wide characterDefined in header

fgetwcgetwc

(C95)

gets a wide character from a file stream
(function)

fgetws

(C95)

gets a wide string from a file stream
(function)

fputwcputwc

(C95)

writes a wide character to a file stream
(function)

fputws

(C95)

writes a wide string to a file stream
(function)

getwchar

(C95)

reads a wide character from

(function)

putwchar

(C95)

writes a wide character to

(function)

ungetwc

(C95)

puts a wide character back into a file stream
(function)

Formatted input/output Narrow characterDefined in header

scanffscanfsscanfscanf_sfscanf_ssscanf_s

(C11)(C11)(C11)

reads formatted input from

, a file stream or a buffer
(function)

vscanfvfscanfvsscanfvscanf_svfscanf_svsscanf_s

(C99)(C99)(C99)(C11)(C11)(C11)

reads formatted input from

, a file stream or a buffer
using variable argument list
(function)

printffprintfsprintfsnprintfprintf_sfprintf_ssprintf_ssnprintf_s

(C99)(C11)(C11)(C11)(C11)

prints formatted output to

, a file stream or a buffer
(function)

vprintfvfprintfvsprintfvsnprintfvprintf_svfprintf_svsprintf_svsnprintf_s

(C99)(C11)(C11)(C11)(C11)

prints formatted output to

, a file stream or a buffer
using variable argument list
(function)

Wide characterDefined in header

wscanffwscanfswscanfwscanf_sfwscanf_sswscanf_s

(C95)(C95)(C95)(C11)(C11)(C11)

reads formatted wide character input from

, a file stream or a buffer
(function)

vwscanfvfwscanfvswscanfvwscanf_svfwscanf_svswscanf_s

(C99)(C99)(C99)(C11)(C11)(C11)

reads formatted wide character input from

, a file stream
or a buffer using variable argument list
(function)

wprintffwprintfswprintfwprintf_sfwprintf_sswprintf_ssnwprintf_s

(C95)(C95)(C95)(C11)(C11)(C11)(C11)

prints formatted wide character output to

, a file stream or a buffer
(function)

vwprintfvfwprintfvswprintfvwprintf_svfwprintf_svswprintf_svsnwprintf_s

(C95)(C95)(C95)(C11)(C11)(C11)(C11)

prints formatted wide character output to

, a file stream
or a buffer using variable argument list
(function)

File positioning Defined in header

ftell

returns the current file position indicator
(function)

fgetpos

gets the file position indicator
(function)

fseek

moves the file position indicator to a specific location in a file
(function)

fsetpos

moves the file position indicator to a specific location in a file
(function)

rewind

moves the file position indicator to the beginning in a file
(function)

Error handling Defined in header

clearerr

clears errors
(function)

feof

checks for the end-of-file
(function)

ferror

checks for a file error
(function)

perror

displays a character string corresponding of the current error to

stderr

(function)

Operations on files Defined in header

remove

erases a file
(function)

rename

renames a file
(function)

tmpfiletmpfile_s

(C11)

returns a pointer to a temporary file
(function)

tmpnamtmpnam_s

(C11)

returns a unique filename
(function)