Re: 3.77.3.99 vs. 3.81 and defines

[Paul D. Smith]

%% "PATTON, BILLY \(SBCSI\)" <address@hidden> writes:

  pb> But one had
  pb> <tab><tab>define yyy
  pb> ...
  pb> <tab><tab>endef

  pb> The one above worked fine on 3.77 and 3.79,  but 3.81 crashes and says
  pb> that it cannot find a matching endef

Hm.  "Crashes"?  Typically that means it dumps core or otherwise behaves
badly.  If that happens please definitely file a bug on Savannah with a
test case.

To know whether the above is a real error or not we'd have to see more
details and/or a reproducible test case.  However, if the behavior is as
you say above then I suspect that this is a bug.

  pb> Now when management asks questions like :
  pb> 1. why wasn't this a problem before?
  pb> 2. Will it effect all the other systems still configured with 3.77 and
  pb> 3.79.

  pb> We need to know that it will not effect all production by making
  pb> this change.  To my knowledge it should not effect anything,
  pb> especially we will be changing a unique instance to make it like
  pb> all others.  Do you agree?

In fact, the example above I would consider a bug in your makefile.
Even if it seems to work.

Remember that _any_ line in a makefile that begins with a TAB is not a
make command line, but rather a shell command script!  _ANY_ line.  Make
does not attempt to look at the contents to decide if it really looks
like a make command or not: if the line begins with a TAB, then make
sticks it into the command script and goes to the next line.


There is one exception, mainly for backward-compatibility.  If there is
no current target being defined, so that the line beginning with a TAB
could not be part of a command script, rather than reporting a syntax
error make will assume it's a make command line and process it that way.


So, in your case, AS LONG AS your defines are never in a position where
they could be considered part of a command script, prefixing them with
TABs like this will work.

But, if someone comes along later and makes some changes so that this is
no longer true, your makefile will fail in not-so-obvious ways.


Rule of thumb for make sanity: NEVER, EVER use a TAB in column 1
ANYWHERE except within a command script.

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