fscanf, fwscanf

Visual Studio 6.0

Read formatted data from a stream.

int fscanf( FILE *stream, const char *format [, argument ]... );

int fwscanf( FILE *stream, const wchar_t *format [, argument ]... );

Function Required Header Compatibility
fscanf <stdio.h> ANSI, Win 95, Win NT
fwscanf <stdio.h> or <wchar.h> ANSI, Win 95, Win NT

For additional compatibility information, see Compatibility in the Introduction.


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

Each of these functions returns the number of fields successfully converted and assigned; the return value does not include fields that were read but not assigned. A return value of 0 indicates that no fields were assigned. If an error occurs, or if the end of the file stream is reached before the first conversion, the return value is EOF for fscanf or WEOF for fwscanf.



Pointer to FILE structure


Format-control string


Optional arguments


The fscanf function reads data from the current position of stream into the locations given by argument (if any). Each argument must be a pointer to a variable of a type that corresponds to a type specifier in format. format controls the interpretation of the input fields and has the same form and function as the format argument for scanf; see scanf for a description of format. If copying takes place between strings that overlap, the behavior is undefined.

fwscanf is a wide-character version of fscanf; the format argument to fwscanf 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
_ftscanf fscanf fscanf fwscanf

For more information, see Format Specification Fields – scanf functions and wscanf Functions.


/* FSCANF.C: This program writes formatted
 * data to a file. It then uses fscanf to
 * read the various data back from the file.

#include <stdio.h>

FILE *stream;

void main( void )
   long l;
   float fp;
   char s[81];
   char c;

   stream = fopen( "fscanf.out", "w+" );
   if( stream == NULL )
      printf( "The file fscanf.out was not opened\n" );
      fprintf( stream, "%s %ld %f%c", "a-string",
               65000, 3.14159, 'x' );

      /* Set pointer to beginning of file: */
      fseek( stream, 0L, SEEK_SET );

      /* Read data back from file: */
      fscanf( stream, "%s", s );
      fscanf( stream, "%ld", &l );

      fscanf( stream, "%f", &fp );
      fscanf( stream, "%c", &c );

      /* Output data read: */
      printf( "%s\n", s );
      printf( "%ld\n", l );
      printf( "%f\n", fp );
      printf( "%c\n", c );

      fclose( stream );



Stream I/O Routines

See Also   _cscanf, fprintf, scanf, sscanf