access read / write violation with ctypes

[Dave Angel]

DH wrote:
> <snip>
>
> I'm using popen to capture dcraw stdout and want to pass it to
> magickwand. If I instead write the dcraw output to a file then read it
> with magickwand I get the same error. But if I comment out the dcraw
> protion and read the dcraw output file from the previous attempt,
> MagickWand opens the file fine and I can manipulate it to my hearts
> content. The basics:
>
> <snip>
>   
Just a quick guess, based only on this paragraph.  But I'd guess the 
dcraw output file is buffered, and is not fully written when you're 
trying to read it back.

You could do some checking by comparing sizes, when you get it from the 
pipe, and when you see it finally written in the directory.

DaveA