bugmake - Bugs: bug #16531, Substitution reference and...

 
 

bug #16531: Substitution reference and secondary expansion

Submitter:  None
Submitted:  Fri 05 May 2006 03:36:39 PM UTC
   
 
Severity:  3 - Normal Priority:  5 - Normal
Item Group:  Bug Status:  Not A Bug
Privacy:  Public Assigned to:  psmith
Open/Closed:  Closed Component Version:  3.81
Operating System:  POSIX-Based Fixed Release:  None
Triage Status:  None
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Sun 04 Mar 2012 03:26:51 PM UTC, comment #4: 

I think the original description is not a bug.  As I said in my comment #3, because make is not parsing the contents of the parens as a variable reference (because we've escaped it), it's treating the ":" as a special character.  I think this is just the behavior we have to accept: ":" is a special character to make, just like "$" and "%" (in some contexts) so it needs to be escaped sometimes.  This is not always obvious but I don't see any way to make it better.

The separate issue, that escaping the colon causes problems, will be addressed by bug #16545.

Paul D. Smith <psmith>
Group administrator
Sun 07 May 2006 06:57:37 PM UTC, comment #3: 

The OP is correct: it's not the "%", it's the ":".  Because the variable reference is escaped, make doesn't skip over it when parsing the command line like it normally would, and instead make sees the second ":" inside the substitution reference and interprets the command as a static pattern rule (any command with two colons on the line is interpreted that way).

I tried to escape the ":" with a backslash and got a core dump (!) which I've reported as bug #16545.

Paul D. Smith <psmith>
Group administrator
Sun 07 May 2006 07:28:36 AM UTC, comment #2: 


> GNU make gets confused by the % in your patsubst call.

The secondary expansion of GNU make is not that much bad. The
putsubst call works perfect without any kind of workarounds.

What the problem is "substitution reference".


.PHONY: foo.bar
.SECONDEXPANSION:
foo: $$(@:%=%.bar); @echo $^
--------
Makefile:3: * target pattern contains no `%'.  Stop.

Anonymous
Fri 05 May 2006 07:09:45 PM UTC, comment #1: 

GNU make gets confused by the % in your patsubst call. You will need to add an indirection:

.PHONY: foo.bar
.SECONDEXPANSION:
p := %
foo: $$(patsubst $p,$p.bar,$$@); @echo $^

Boris Kolpackov <bosk>
Group Member
Fri 05 May 2006 03:36:39 PM UTC, original submission:  

The make doesn't recognize substitution references while the
secondary expansion. I don't find any restrictive note about
this in the manual either.


--------
.PHONY: foo.bar

.SECONDEXPANSION:
#foo: $$(patsubst %,%.bar,$$@)
foo: $$(@:%=%.bar)
\t@echo $^
--------
Makefile:5: * target pattern contains no `%'.  Stop.

Anonymous

 

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    History

    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2012-03-04 psmith StatusNone Not A Bug
        Assigned toNone psmith
        Open/ClosedOpen Closed

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