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Posted by Mike Ford on 01/07/05 13:43
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On 07 January 2005 00:20, Jason Barnett wrote:
> That was what I thought also. However just to add to the
> confusion: I
> think require'd files were evaluated no matter what back in
> PHP4. Even
> if they were part of a conditional. At least that's my
> recollection of
> it; I haven't used PHP4 since 4.3.2 ;)
Back in about 4.0.2 or .3, that was the case; the current behaviour has been
in place since at least 4.0.5.
> Bottom line: I always require_once at the top of a file for any files
> that I will require. No sense in doing anything else if the required
> files aren't there. For conditionally including files include_once()
> has always made the most sense to me.
I'm not sure that's the best strategy: since include() will continue
executing your script even if the file does not exist, you shouldn't use
include() if anything which follows will fail in the absence of the
(non-)included code. If the content of the other file is essential to the
correct operation of your script, you should use require(), since that will
terminate with a fatal error if the required file is not present.
It makes sense to require() files in a conditional branch if *only* the code
in that branch is dependent on the required file. If all (or at least
enough) branches rely on the file, then requiring it at the top of the file
is a sensible move.
Whether you use the basic include()/require() or the _once versions depends
on whether you want the code in the file to be executed each time the
require/include is executed or not. For initialization of constants or
parameter variables, the _once versions make sense; for code which contains
substantive logic or output, it may not, especially if inside a loop.
Cheers!
Mike
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Mike Ford, Electronic Information Services Adviser,
Learning Support Services, Learning & Information Services,
JG125, James Graham Building, Leeds Metropolitan University,
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Email: m.ford@leedsmet.ac.uk
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