[metapost] mpost returns 1 on successful run?

[Taco Hoekwater]

Hi Norbert,

Norbert Preining wrote:
> Hi Taco,
> 
> on the Debian side we got a bug report that with the switch from 
> TL2007 mpost to TL2009 mpost the same file suddenly makes mpost
> return 1 (failure in shell) instead of 0.

Any issued diagnostic messages set the return code to 1. Issued errors
are 2, issued fatal errors give 3.

It has been like that in the original sources since the eighties,
just as in TeX (but possibly there was a special patch in web2c
earlier that reverted 1 back to 0, I don't know)

So yes, that is intended. Error return codes start at 2.

Best wishes,
Taco