libsndfile error handling

[FabricioS]

Hi David,
using audiolab for a few years, I looked to the TODO list (in the docs) to see if I could help somehow. You wrote one of the next goal is to «support the libsndfile’s error system».

If i understand http://www.mega-nerd.com/libsndfile/api.html#error , each call to functions sf_xxx taking a SndFile pointer as input is able to store a error code in this structure (less sf_open and sf_open_fd that return a NULL pointer in case of failed opening of file). Do you confirm that to support this error system, we need to check the error code (through the sf_error function). If non zero, next step is to invoke sf_strerror to get a description of error and raise the adequate pythonic exception.

Are you OK with that?

[FabricioS]

It seems that you were kind of aware of that. I am not sure the way you used the sf_strerror on the NULL pointer (L480 in _sndfile.pyx) is the right one.
I would use it after sf_read/write (correct number of items with respect to number of channels), sf_seek and sf_get/set_string functions call.