Php optional parameter array

You can pass a variable by reference to a function so the function can modify the variable. The syntax is as follows: There is no reference sign on a function call - only on function definitions. Function definitions alone are enough to correctly pass the argument by reference.

PHP: Function arguments - Manual

As of PHP 5. And as of PHP 5.

The following things can be passed by reference: No other expressions should be passed by reference, as the result is undefined. For example, the following examples of passing by reference are invalid: Getting Started Introduction A simple tutorial Language Reference Basic syntax Types Variables Constants Expressions Operators Control Structures Functions Classes and Objects Namespaces Errors Exceptions Generators References Explained Predefined Variables Predefined Exceptions Predefined Interfaces and Classes Context options and parameters Supported Protocols and Wrappers Security Introduction General considerations Installed as CGI binary Installed as an Apache module Session Security Filesystem Security Database Security Error Reporting Using Register Globals User Submitted Data Magic Quotes Hiding PHP Keeping Current Features HTTP authentication with PHP Cookies Sessions Dealing with XForms Handling file uploads Using remote files Connection handling Persistent Database Connections Safe Mode Command line usage Garbage Collection DTrace Dynamic Tracing Function Reference Affecting PHP's Behaviour Audio Formats Manipulation Authentication Services Command Line Specific Extensions Compression and Archive Extensions Credit Card Processing Cryptography Extensions Database Extensions Date and Time Related Extensions File System Related Extensions Human Language and Character Encoding Support Image Processing and Generation Mail Related Extensions Mathematical Extensions Non-Text MIME Output Process Control Extensions Other Basic Extensions Other Services Search Engine Extensions Server Specific Extensions Session Extensions Text Processing Variable and Type Related Extensions Web Services Windows Only Extensions XML Manipulation GUI Extensions Keyboard Shortcuts?

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Passing by Reference You can pass a variable by reference to a function so the function can modify the variable. By removing the ability to include the reference sign on function calls where pass-by-reference is incurred I. If both function calls and function definitions require the reference sign I.

Going full on fatal error in 5. That is, does a function merely use the variable, or potentially modify it The comment by tnestved at yahoo dot com is incorrect as it is based purely on perception and not architecture. The method passing the object should not care whether it is by ref or by val, and nor should the reader.

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If we are talking about readability and perception, then the receiving method needs to show that the object coming in is a reference, not an object instance, otherwise the reader is perplexed why the object is not returned. Good functional headers alleviate all issues in this case. The notes indicate that a function variable reference will receive a deprecated warning in the 5. This is not a "bug" since it is not likely worth resolving, however should be noted in this documentation.

Some have noticed that reference parameters can not be assigned a default value.

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It's actually wrong, they can be assigned a value as the other variables, but can't have a "default reference value", for instance this code won't compile: Sometimes we need functions for building or modifying arrays whose elements are to be references to other variables arrays or objects for instance. In this example, I wrote two functions 'tst' and 'tst1' that perform this task.

PHP: scandir - Manual

Note how the functions are written, and how they are used. I hope this is somehow useful Sergio. Just a simple note The second code "explains" how passage of parameters by reference works.

PHP has a strange behavior when passing a part of an array by reference, that does not yet exist.