Section 16.1. Input and Output

16.1. Input and Output

We have dealt with this topic in detail in Chapter 13, which contains sections on I/O streams, sequential and random file access , formatted I/O, and error handling. A tabular list of the I/O functions will therefore suffice here. Table 16-1 lists general file access functions declared in the header stdio.h.

Table 16-1. General file access functions

Purpose	Functions
Rename a file, delete a file	rename( ), remove( )
Create and/or open a file	fopen( ), freopen( ), tmpfile( )
Close a file	fclose( )
Generate a unique filename	tmpnam( )
Query or clear file access flags	feof( ), ferror( ), clearerr( )
Query the current file access position	ftell( ), fgetpos( )
Change the current file access position	rewind( ), fseek( ), fsetpos( )
Write buffer contents to file	fflush( )
Control file buffering	setbuf( ), setvbuf( )

There are two complete sets of functions for input and output of characters and strings: the byte-character and the wide-character I/O functions (see "Byte-Oriented and Wide-Oriented Streams" in Chapter 13 for more information). The wide-character functions operate on characters with the type wchar_t, and are declared in the header wchar.h. Table 16-2 lists both sets.

Table 16-2. File I/O functions

Purpose	Functions in stdio.h	Functions in wchar.h
Get/set stream orientation		fwide( )
Write characters	fputc( ), putc( ), putchar( )	fputwc( ), putwc( ), putwchar( )
Read characters	fgetc( ), getc( ), getchar( )	fgetwc( ), getwc( ), getwchar( )
Put back characters read	ungetc( )	ungetwc( )
Write lines	fputs( ), puts( )	fputws( )
Read lines	fgets( ), gets( )	fgetws( )
Write blocks	fwrite( )
Read blocks	fread( )
Write formatted strings	printf( ), vprintf( ) fprintf( ), vfprintf( ) sprintf( ), vsprintf( ) snprintf( ), vsnprintf( )	wprintf( ), vwprintf( ) fwprintf( ), vfwprintf( ) swprintf( ), vswprintf( )
Read formatted strings	scanf( ), vscanf( ) fscanf( ), vfscanf( ) sscanf( ), vsscanf( )	wscanf( ), vwscanf( ) fwscanf( ), vfwscanf( ) swscanf( ), vswscanf( )