PHP 5 and 7

Traditional assertions (PHP 5 and 7)

If the assertion is given as a string it will be evaluated as PHP code by assert(). If you pass a boolean condition as assertion , this condition will not show up as parameter to the assertion function which you may have defined with assert_options(). The condition is converted to a string before calling that handler function, and the boolean FALSE is converted as the empty string.

Assertions should be used as a debugging feature only. You may use them for sanity-checks that test for conditions that should always be TRUE and that indicate some programming errors if not or to check for the presence of certain features like extension functions or certain system limits and features.

Assertions should not be used for normal runtime operations like input parameter checks. As a rule of thumb your code should always be able to work correctly if assertion checking is not activated.

The behavior of assert() may be configured by assert_options() or by .ini-settings described in that functions manual page.

The assert_options() function and/or ASSERT_CALLBACK configuration directive allow a callback function to be set to handle failed assertions.

assert() callbacks are particularly useful for building automated test suites because they allow you to easily capture the code passed to the assertion, along with information on where the assertion was made. While this information can be captured via other methods, using assertions makes it much faster and easier!