programing the vex optical shaft encoder

[youngWilliam14]

ok now i have another problem:

while (swerve == 0)
{
      Tank4 (0 , 2 , 2 , 3 , 4 , 1 , 2 , 1 , 0 , 1 , 0);
       swerve = GetRxInput (1 , 5);
}

the variable 'swerve' is set to 0 when i press the lower ch. 5 button. i'm still holding the button down when i get to this part of the code, but it skips the while loop and goes right to trying to turn the wheels back to zero. does anyone know why the loop gets skipped, even though the value of 'swerve' is still 0? the only reason why the program gets to that point is because it's allredy checked to see if the button is being pressed