vfscanf()

QNX SDP8.0C Library ReferenceAPIDeveloper

Scan input from a file (varargs)

Synopsis:

#include <stdio.h>
#include <stdarg.h>

int vfscanf( FILE *fp,
             const char *format,
             va_list arg );

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.
arg
A variable-argument list of the additional arguments, which you must have initialized with the va_start() macro.

Library:

libc

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

Description:

The vfscanf() function scans input from the file designated by fp, under control of the argument format.

The vfscanf() function is a varargs version of fscanf().

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

Returns:

The number of input arguments for which values were successfully scanned and stored, or EOF when the scanning is stopped by reaching the end of the input stream before storing any values.

Errors:

If an error occurs, errno indicates the type of error.

Examples:

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

void ffind( FILE *fp, char *format, ... )
  {
    va_list arglist;

    va_start( arglist, format );
    vfscanf( fp, format, arglist );
    va_end( arglist );
  }

int main( void )
  {
    int day, year;
    char weekday[10], month[12];

    ffind( stdin,
        "%10s %12s %d %d",
        weekday, month, &day, &year );
    printf( "\n%s, %s %d, %d\n",
        weekday, month, day, year );
    return EXIT_SUCCESS;
  }

Classification:

ANSI, POSIX 1003.1

Safety:
Cancellation pointNo
Signal handlerNo
ThreadYes
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