Not sure if you need to worry about it so much. PHP5 does a "copy on write" (and a default pass by reference) basically. And references are more like unix symlinks than C pointers. http://us3.php.net/manual/en/language.references.php http://bytes.com/groups/php/769586-copy-write-semantic http://blog.libssh2.org/index.php?/archives/51-Youre-being-lied-to..html I suspect your nested functions call overhead is more expensive than accessing your variables/arrays and you might consider in-lining it more. http://www.hudzilla.org/phpbook/read.php/18_1_3 But then again, this seems to contradict this theory a bit in newer PHP versions: http://www.webhostingtalk.com/showthread.php?t=538076 http://www.garfieldtech.com/blog/magic-benchmarks http://shootout.alioth.debian.org/gp4/benchmark.php?test=all&lang=php&lang2=php On Wed, 2009-02-18 at 10:53 +1100, Clancy wrote: > I have a function to process a data file. This process opens the file, and then calls > another function to process each entry. This function in turn calls another function to > process each line of the entry. A set of fairly complex arrays specifies how all the > possible types of entries and lines should be processed, and each function passes sections > of these arrays to the next function. > > Is it better to pass the parameters by value, in which case they have to be copied into > yet more memory when the function is called, or to pass by reference, which I suspect may > involve additional overhead every time they are accessed? > > And is it better to combine several specifications arrays into one more complex array, and > pass a single parameter, or to pass them individually as half a dozen different > parameters? > > I suspect that I am probably asking a "how long is a piece of string?" type of question, > but are there any general rules which are applicable to this type of situation? >
