File

Overview of functions

Most of the C file input/output functions are defined in stdio.h (cstdio header in C++).

	Byte character	Wide character	Description
File access	fopen		opens a file
	freopen		opens a different file with an existing stream
	fflush		synchronizes an output stream with the actual file
	fclose		closes a file
	setbuf		sets the buffer for a file stream
	setvbuf		sets the buffer and its size for a file stream
	fwide		switches a file stream between wide character I/O and narrow character I/O
Direct input/output	fread		reads from a file
	fwrite		writes to a file
Unformatted input/output	fgetc getc	fgetwc getwc	reads a byte/wchar_t from a file stream
	fgets	fgetws	reads a byte/wchar_t line from a file stream
	fputc putc	fputwc putwc	writes a byte/wchar_t to a file stream
	fputs	fputws	writes a byte/wchar_t string to a file stream
	getchar	getwchar	reads a byte/wchar_t from stdin
	gets	N/A	reads a byte string from stdin (deprecated in C99, obsoleted in C11)
	putchar	putwchar	writes a byte/wchar_t to stdout
	puts	N/A	writes a byte string to stdout
	ungetc	ungetwc	puts a byte/wchar_t back into a file stream
Formatted input/output	scanf fscanf sscanf	wscanf fwscanf swscanf	reads formatted byte/wchar_t input from stdin, a file stream or a buffer
	vscanf vfscanf vsscanf	vwscanf vfwscanf vswscanf	reads formatted input byte/wchar_t from stdin, a file stream or a buffer using variable argument list
	printf fprintf sprintf snprintf	wprintf fwprintf swprintf	prints formatted byte/wchar_t output to stdout, a file stream or a buffer
	vprintf vfprintf vsprintf vsnprintf	vwprintf vfwprintf vswprintf	prints formatted byte/wchar_t output to stdout, a file stream, or a buffer using variable argument list
	perror	N/A	writes a description of the current error to stderr
File positioning	ftell		returns the current file position indicator
	fgetpos		gets the file position indicator
	fseek		moves the file position indicator to a specific location in a file
	fsetpos		moves the file position indicator to a specific location in a file
	rewind		moves the file position indicator to the beginning in a file
Error handling	clearerr		clears errors
	feof		checks for the end-of-file
	ferror		checks for a file error
Operations on files	remove		erases a file
	rename		renames a file
	tmpfile		returns a pointer to a temporary file
	tmpnam		returns a unique filename