fscanf()

Scan input from a stream

Synopsis:

#include <stdio.h>

int fscanf( FILE* fp, 
            const char* format, 
            ... );

Arguments:

fp: The stream that you want to read from.
format: A string that specifies the format of the input. For more information, see scanf(). The formatting string determines what additional arguments you need to provide.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The fscanf() function scans input from the stream specified by fp, under control of the argument format.

Note: The fscanf() function is generally considered unsafe for string handling; it's safer to use fgets() to get a line of input and then use sscanf() to process the input.

Returns:

The number of input arguments for which values were successfully scanned and stored, or EOF if the scanning reached the end of the input stream before storing any values (errno is set).

Examples:

Scan a date in the form “Friday March 26 1999”:

#include <stdio.h>
#include <stdlib.h>

int main( void )
{
    int day;
    int year;
    char weekday[10];
    char month[10];
    FILE *in_data;

    in_data = fopen( "file", "r" );
    if( in_data != NULL ) {
        fscanf( in_data, "%10s %10s %d %d",
                weekday, month, &day, &year );

        printf( "Weekday=%s Month=%s Day=%d Year=%d\n",
                weekday, month, day, year );

        fclose( in_data );
        
        return EXIT_SUCCESS;
    }
    
    return EXIT_FAILURE;
}

Classification:

ANSI, POSIX 1003.1

Safety:
Cancellation point	Yes
Interrupt handler	No
Signal handler	No
Thread	Yes