fprintf, fwprintf
Print formatted data to a stream.
intfprintf(FILE*stream,constchar*format [, argument ]...);
intfwprintf(FILE*stream,constwchar_t*format [, argument ]...);
| Function | Required Header | Compatibility |
| fprintf | <stdio.h> | ANSI, Win 95, Win NT |
| fwprintf | <stdio.h> or <wchar.h> | ANSI, Win 95, Win NT |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
| LIBC.LIB | Single thread static library, retail version |
| LIBCMT.LIB | Multithread static library, retail version |
| MSVCRT.LIB | Import library for MSVCRT.DLL, retail version |
Return Value
fprintf returns the number of bytes written. fwprintf returns the number of wide characters written. Each of these functions returns a negative value instead when an output error occurs.
Parameters
stream
Pointer to FILE structure
format
Format-control string
argument
Optional arguments
Remarks
fprintf formats and prints a series of characters and values to the output stream. Each function argument (if any) is converted and output according to the corresponding format specification in format. For fprintf, the format argument has the same syntax and use that it has in printf.
fwprintf is a wide-character version of fprintf; in fwprintf, format is a wide-character string. These functions behave identically otherwise.
Generic-Text Routine Mappings
| TCHAR.H Routine | _UNICODE & _MBCS Not Defined | _MBCS Defined | _UNICODE Defined |
| _ftprintf | fprintf | fprintf | fwprintf |
For more information, see Format Specifcations.
Example
/* FPRINTF.C: This program uses fprintf to format various
* data and print it to the file named FPRINTF.OUT. It
* then displays FPRINTF.OUT on the screen using the system
* function to invoke the operating-system TYPE command.
*/
#include <stdio.h>
#include <process.h>
FILE *stream;
void main( void )
{
int i = 10;
double fp = 1.5;
char s[] = "this is a string";
char c = '\n';
stream = fopen( "fprintf.out", "w" );
fprintf( stream, "%s%c", s, c );
fprintf( stream, "%d\n", i );
fprintf( stream, "%f\n", fp );
fclose( stream );
system( "type fprintf.out" );
}
Output
this is a string
10
1.500000