Re: [pdf-devel] Confusion about return values

[jemarch]

   I'm trying to get the unit tests to pass, and I'm getting failures
   in the file stream tests. I'll fix up the code, but I need to
   understand what is intended.

   pdf_stm_t pdf_create_file_stm (char *filename, int mode)
   I take it that this is meant to return a file object, or NULL on
   failure.

Right.

   The code is wrong, because it checks the return value of the backend init 
   function against NULL, but the function signature in struct pdf_stm_be_s is 
   int (*init) (void **be_data, void *conf_data);
   and the file backend returns PDF_OK or PDF_ERROR

   Is the intent that the backend init() return value is really a
   pdf_status_t? 

Yes.

   If so, why it is the signature an int?

That signature is wrong. It should be:

pdf_status_t (*init) (void **be_data, void *conf_data);

The same for the other backend functions.

   Same logic applies for most of the other backend functions. The unit tests 
   contain checks like:
     fail_if (!pdf_stm_close (stm));
   which IMHO would be a lot clearer if it checked against PDF_OK.

I agree. Would be much better to write those checks as:

   fail_if (pdf_stm_close (stm) != PDF_OK);