PHP checks whether the extension library or function is available. The functions described in this article are actually available in the PHP Manual. However, these functions are independent and difficult to find, so we will introduce them separately for easy reference. 1. obtain all the available functions. the functions described in this article are actually available in the PHP Manual. However, these functions are independent and difficult to find, so I will introduce them separately for your convenience.
1. get all available modules-get_loaded_extensions this function returns all loaded (available) modules.
Usage:
The code is as follows:
Print_r (get_loaded_extensions ());
2. obtain the available functions of the specified module-get_extension_funcs. This function returns all available functions of the specified module. The input parameter (module name) must be in lowercase.
Usage:
The code is as follows:
Print_r (get_extension_funcs ("gd "));
3. get all defined functions-get_defined_functions this function returns all defined functions, including built-in functions and user-defined functions.
Usage:
The code is as follows:
Function myrow ($ id, $ data ){
Return"$ Id$ Data\ N ";
}
$ Arr = get_defined_functions ();
Print_r ($ arr );
Output:
The code is as follows:
Array
(
[Internal] => Array
(
[0] => zend_version
[1] => func_num_args
[2] => func_get_arg
[3] => func_get_args
[4] => strlen
[5] => strcmp
[6] => strncmp
...
[1, 750] => bcscale
[751] => bccomp
)
[User] => Array
(
[0] => myrow
)
)
$ Arr ["internal"] is a built-in function, and $ arr ["user"] is a user-defined function.
4. check whether the specified function exists-function_exists. This function returns whether the specified function has been defined.
Usage:
The code is as follows:
If (function_exists ('imap _ open ')){
Echo "IMAP functions are available.
\ N ";
} Else {
Echo "IMAP functions are not available.
\ N ";
}
Bytes. 1. get all available...