After a 2-second search of the PHP manual...

"require() and include() are identical in every way except how they handle
failure. include() produces a Warning while require() results in a Fatal
Error. In other words, don't hesitate to use require() if you want a missing
file to halt processing of the page. include() does not behave this way, the
script will continue regardless. Be sure to have an appropriate include_path
setting as well."


"The include_once() statement includes and evaluates the specified file
during the execution of the script. This is a behavior similar to the
include() statement, with the only difference being that if the code from a
file has already been included, it will not be included again. As the name
suggests, it will be included just once."

> -----Original Message-----
> From: Mikhail U. Petrov [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, April 13, 2004 2:07 PM
> To: Eric Girard
> Cc: Karen Resplendo; [EMAIL PROTECTED]
> Subject: Re[2]: [PHP-DB] Curious if include_once will work better than
> include
> Hi!
> Sorry for my offtopic, but by the way,
> what's the difference between include/include_once and
> require/require_once?
> Tuesday, April 13, 2004, 10:29:14 PM, Eric wrote:
> >> Curious about "include_once" versus "include".
> >>
> >> All my connection stuff is in "conn.php3".
> >>
> >> I am planning on including it at the top of the page like this:
> >> include_once "conn.php3";
> >>
> >> Now will that speed things up compared to just using a 
> plain "include". I
> >> call $connectionSDWIS(which is in the include) 5 different times?
> EG> IMHO the 'speed' difference between include and 
> include_once will be
> EG> slight, probably with include_once being slower because 
> of the overhead
> EG> needed to keep track of which files have been included 
> already.  But this
> EG> isn't really what the question is about.  include and 
> include_once will
> EG> not magically optimize the code for you, but if you 
> include the same file
> EG> 20 times that will be more that has to be parsed 
> needlessly, so if you
> EG> can't keep track of your includes or if including a 
> particular file more
> EG> than once will alter the result, than use include_once. Another
> EG> alternative is to use require() or require_once() to make 
> sure that the
> EG> file is included.   Just my $.02,
> EG> Eric
> -- 
> Best regards,
> Mikhail U. Petrov
> -- 
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