Re: [bug #51311] Checking search retries for implicit make rules

[Philip Guenther]

On Sun, 25 Jun 2017, Mike Gran wrote:
> Follow-up Comment #1, bug #51311 (project make): You've opened this as a 
> bug. I believe it is not a bug.  Again. I'm not a maintainer.
> 
> Please note two things.
> 
> 1. while "MOTD%.log: MOTD%.txt" is a pattern rule, "MOTD%.log: MOTD%.txt
> MOTD%.in" is not a pattern rule, because it has two entries after the colon. 

This is incorrect.  To quote the make info pages, section 10.5.1
"Introduction to Pattern Rules":
-----
A pattern rule contains the character `%' (exactly one of them) in the
target; otherwise, it looks exactly like an ordinary rule.  The target
is a pattern for matching file names; the `%' matches any nonempty
substring, while other characters match only themselves.  
-----

There's no restriction in the documention on the number of prequisites on 
the rule and they may contain any mix of pattern and non-pattern names.  
See that page and the others in that section for further details.



> 2. The '%' (the stem) in a pattern rule doesn't, if I recall correctly, match
> a null string.  It needs to match at least a single character, so building
> MOTD.log won't work.

This is correct, as per the documentation quoted above.


Philip Guenther