Re: [Bug-ddrescue] 2 Suggestions (bi-directional retry and user interruption exit code)

[Antonio Diaz Diaz]

Scott D wrote:
> This is with non-modified ddrescue.

Then Ctrl-c can't be reliably differentiated from a normal exit with 0 
status.


> I was looking at the return value 
> raw, not using the proper WEXITSTATUS, and found it to not be zero if 
> terminated by ctrl-c. I believe the value would was 0x0200, showing the 
> SIGNT as the high order byte.

You can't use the status returned by waitpid this way. It includes 
several values and must be tested with the corresponding macros[1] like 
this:

  if( WIFEXITED( status ) ) return WEXITSTATUS( status );

[1]http://www.gnu.org/software/libc/manual/html_node/Process-Completion-Status.html


> So I do believe that the only sure way to tell if 
> ddrescue was terminated by the user is to make it exit with a nonzero 
> value.

It is the safest option (in case someone uses 'status & 0xFF' as return 
value), but it is quite a change to consider an user-finished run as an 
error.