How to halt program until file input?

Hi, I am making an image processing program and want to know if there is a way to halt the program and make it wait for a image to be created before it is read. To put it into context,

imagefiles = dir('*.jpg');
nfiles = length(imagefiles);

for a = 1:200
    filename = ['image-' num2str(a,'%02d') '.jpg'];
    image = imread(filename);

I understand pause(n) might work but because the inputted images take different times to be snapped, I would like to make it dependent on when the file appears.

Any suggestions would be great!

Answer 1

[Joseph Cheng]

You could put in a while loop checking whether the file exist().

count = 0;
while exist(filename)==0
 pause(1)
 count = count+1;
 if count ==10000
   disp('no file was generated in allowed time');
   break
end

I also put in a simple time out as well. I suggest you put in a

[Michael]

Didn't know I could use the function "exist" with the "filename" variable. Thanks for the help!