Syntax

#include <io.h>
int isatty(int handle);

isatty determines whether the given handle is associated with a character device (a keyboard, display, or printer or serial port).

Note: In earlier releases of C Set ++, isatty began with an underscore (_isatty). Because it is defined by the X/Open standard, the underscore has been removed. For compatibility, The Developer's Toolkit will map _isatty to isatty for you.

isatty returns a nonzero value if the device is a character device. Otherwise, the return value is 0.

This example opens the console and determines if it is a character device:

#include <io.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys\stat.h>

int main(void)
{
   int fh,result;

   if (-1 == (fh = open("CON", O_RDWR, (S_IREAD|S_IWRITE)))) {
      perror("Error opening console\n");
      return EXIT_FAILURE;
   }
   result = isatty(fh);
   if (0 != result)
      printf("CON is a character device.\n");
   else
      printf("CON is not a character device.\n");
   close(fh);
   return 0;

   /****************************************************************************
      The output should be:

      CON is a character device.
   ****************************************************************************/
}

none

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