The new std.process is ready for review

[Jonathan M Davis]

On Saturday, February 23, 2013 14:46:04 H. S. Teoh wrote:
> I never liked the design of errno in C... its being a global makes
> keeping track of errors a pain. It would be nice if the value of errno
> were saved in the Exception object at the time the error was
> encountered, instead of arbitrary amounts of code after, which may have
> changed its value.

That's what std.exception.errnoEnforce and ErrnoException doe. The 
ErrnoException gets the error code when it's constructed. 
std.file.FileException does the same thing at least some of the time (depending 
on what caused the error). In the case of FileException, we should probably 
have subclasses for the main error codes that you might want to handle 
specially (so catching the explicitly would be useful), but we don't have that 
yet.

I don't know what the new std.process is doing (I haven't look at it yet), but 
if it's throwing exceptions based on errno, it needs to at least put the error 
code in the exception and maybe have specific exception types if it would make 
sense to be catching exceptions from std.process based on what exactly went 
wrong. Get the value of errno after catching the exception is just asking for 
it, since who knows what code ran after the exception was originally thrown.

- Jonathan M Davis