Dealing with exceptions

bvdp bob at mellowood.ca
Sat Mar 2 12:40:11 EST 2013


Every time I write a program with exception handling (and I suppose that includes just about every program I write!) I need to scratch my brain when I create try blocks.

For example, I'm writing a little program do copy specific files to a USB stick. To do the actual copy I'm using:

    try:
       shutil.copy(s, os.path.join(usbpath, songname))
     except ...

now, I need to figure out just what exceptions to handle. Let's see: 

  IOError  that means that the disk is full or otherwise buggered. Better dump out of the loop.

But, I know there can be other errors as well. Doing some tests, I know that certain filenames are invalid (I think a "?" or unicode char is invalid when writing to a FAT32 filesystem). And, so what exception is that? Without actually creating the error, I can't figure it out.

In this case, I can run the program an number of times and parse out the errors and write code to catch various things. But, I think I'm missing something completely. Guess what I'm looking for is a list of possible (probable?) errors for the shutil.copy() command. And, in a much bigger manual, for most other commands.

Maybe I'm just venting about FAT32 filesystems :)




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