Re: Rule formulation

Just add an empty rule for fileB, like so:

fileB:

-Rob

haues1 wrote:
> Hi,
>
> I am trying to formulate a rule for the following task:
>
> The target "fileA" is created by executing the command
> "Cmd_to_create_fileA", which does NOT require the "fileB". There is no rule
> in GnuMake to create "fileB". Still, I would like to make the creation of
> "fileA" dependent on "fileB", according to the conditons:
>
> Execute "Cmd_to_create_fileA"
> 	1) if fileA exists and fileB exists and fileB is younger than fileA;
> 	2) if fileA exists and fileB does not exist;
> 	3) if fileA does not exist and fileB exists;
> 	4) if fileA does not exist and fileB does not exist;
> or, formulated the other way round, do NOT execute "Cmd_to_create_fileA":
> 	if fileA exists and fileB exists and fileB is older than fileA;
>
> The conditions 1) and 3) are covered by the standard rule:
>
>      fileA: fileB
>             Cmd_to_create_fileA
>
> In cases 2) and 4) gnumake doesn't find a rule to create fileB, and aborts
> with an error like "Don't now how to make fileB". How can I formulate the
> rule, so no error occurs?
>
> Can somebody please help me?
>
> Cheers
> Haues
>