fscanf

1 Description
2 Syntax
3 Parameters
4 Return
5 Examples
6 Remark
7 See Also
8 header to Include
9 Reference

Description

Reads data from the current position of stream into the locations given by argument.

Syntax

int fscanf( FILE * stream, const char * format, ... )

Parameters

stream: Pointer to FILE structure
format: Format-control string
...

Return

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.

Examples

EX1

//The following example writes formatted data to a file. It then uses fscanf to read the various data back from the file.

void test_fscanf()
{
        FILE *stream;
        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" );
        else
        {
            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 );
        }
}

Remark

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 printf. If copying takes place between strings that overlap, the behavior is undefined.