>> On Fri, Nov 07, 2003 at 07:19:35PM +0000, David Laight wrote:
>>   | I thought I'd try to stop the build failing when a .depend file
>>   | references an old .h file by changing mkdep so that it adds:
>>   | 
>>   | .OPTIONAL: header.h .....
>>   | 
>>   | This stops the build failing, but the program that depended on the
>>   | deleted .h file is always rebuilt.
>> 
>> I'm not convinced that this is necessary.  I'll defer to the make(1)
>> gurus (sjg@, etc :) if they disagree.

The .OPTIONAL - or at least the concept is what I was talking about the
other day.

>I've had another thought overnight (really ought to get some sleep!):
>- Always run ${CC} with -MD so that EVERY compilation regenerates xxx.d
>- In the ".depend: *.d" rule do the 'twiddling' that mkdep currently
>  does and also add .OPTIONAL for all the headers.
>- Arrange for the .depend file to be regenerated every time a program is
>  built (it is a cheap action)

>I think that would mean that the 'make depend' pass would be unnecessary.

>Has this been tried before?

Yes, this is almost exactly what my autodep.mk does.  It works well.
With the addition of .OPTIONAL it would be perfect.

--sjg

>	David

>-- 
>David Laight: david@l8s.co.uk