Hvorfor brug af "indirection operator" her?!

Hej.

Er der nogen der kan forklare hvorfor man bruger indirection operator i nedenstående while.


/* Demonstrates using the gets() return value. */



#include <stdio.h>



/* Declare a character array to hold input, and a pointer. */



char input[257], *ptr;



int main( void )

{

    /* Display instructions. */



    puts("Enter text a line at a time, then press Enter.");

    puts("Enter a blank line when done.");



    /* Loop as long as input is not a blank line. */



    while ( *(ptr = gets(input)) != NULL)

        printf("You entered %s\n", input);



    puts("Thank you and good-bye\n");



    return 0;

}


Hvorfor er det ikke:    while ( (ptr = gets(input)) != NULL)