Notice: Undefined index: ZZZZZZWTF? [duplicate]

1 Notice: Undefined index: ZZZZZZWTF? [duplicate]

When running the PHP script again, it is clear that there is no problem with the script syntax, but there are the following prompts:

Notice: Undefined index: submit in C:\xampp\htdocs\globalautoparts\register.php on line 36
Notice: Undefined index: fullname in C:\xampp\htdocs\globalautoparts\register.php on line 40
Notice: Undefined index: username in C:\xampp\htdocs\globalautoparts\register.php on line 41
Notice: Undefined index: password in C:\xampp\htdocs\globalautoparts\register.php on line 42
Notice: Undefined index: repeatpassword in C:\xampp\htdocs\globalautoparts\register.php on line 43
Notice: Undefined index: email in C:\xampp\htdocs\globalautoparts\register.php on line 45

In this case, how to solve it.

2 solution

Modify the log prompt level of PHP and ignore these prompts. Add the following statement at the top of the script, and then solve the problem.

error_reporting(E_ALL ^ E_NOTICE);

3 error_reporting() function

3.1 definition and usage

error_ The reporting () function specifies which error to report.

This function sets the error reporting level of the current script.

This function returns the old error reporting level.

3.2 error_ Several common ways of writing in reporting ()

  • error_reporting(E_ALL ^ E_NOTICE ^ E_WARNING): this means reporting except E_ NOTICE, E_ All errors except warning
  • error_reporting(E_WARNING | E_ERROR): this means that only e is reported_ Error and e_ Warning these two levels of error
  • error_ Reporting (E _all & ~ e _note): the same as ^ for reporting except E_ All errors except note

3.3 log level in PHP

valueconstantexplainRemarks (version requirements)
1E_ERRORFatal runtime error. Such errors are generally unrecoverable, such as problems caused by memory allocation. The result is that the script terminates and does not continue to run.
2E_WARNINGRuntime warning (non fatal error). Only prompts are given, but the script does not terminate.
4E_PARSECompile time syntax parsing error. Parsing errors are only generated by the parser.
8E_NOTICERuntime notification. It indicates that the script may encounter errors, but there may be similar notifications in the script that can run normally.
16E_CORE_ERRORA fatal error occurred during PHP initialization startup. This error is similar to E_ERROR, but it is generated by the PHP engine core.since PHP 4
32E_CORE_WARNINGWarning (non fatal error) during PHP initialization startup. Similar to E_WARNING, but it is generated by the PHP engine core.since PHP 4
64E_COMPILE_ERRORFatal compile time error. Similar to E_ERROR, but it is generated by Zend script engine.since PHP 4
128E_COMPILE_WARNINGCompile time warning (non fatal error). Similar to E_WARNING, but it is generated by Zend script engine.since PHP 4
256E_USER_ERRORUser generated error messages. Similar to E_ERROR, but the user himself uses the PHP function trigger in the code_ Error().since PHP 4
512E_USER_WARNINGUser generated warning messages. Similar to E_WARNING, but the user himself uses the PHP function trigger in the code_ Error().since PHP 4
1024E_USER_NOTICEUser generated notification information. Similar to e_ Note, but the user himself uses the PHP function trigger in the code_ Error().since PHP 4
2048E_STRICTEnable PHP to suggest changes to the code to ensure the best interoperability and forward compatibility of the code.since PHP 5
4096E_RECOVERABLE_ERRORFatal errors that can be caught. It indicates that a potentially dangerous error has occurred, but it has not caused the PHP engine to be in an unstable state. If the error is not captured by the user-defined handle (seeset_error_handler() will become an E_ERROR so that the script will terminate. since PHP 5.2.0
8192E_DEPRECATEDRuntime notification. When enabled, warnings will be given to code that may not work properly in future releases.since PHP 5.3.0
16384E_USER_DEPRECATEDWarning message for low user productivity. Similar to E_DEPRECATED, but the user himself uses the PHP function trigger in the code_ Error()since PHP 5.3.0
32767E_ALLE_ All errors and warnings outside strict.32767 in PHP 5.4.x, 30719 in PHP 5.3.x, 6143 in PHP 5.2.x, 2047 previously

3.4 about E_ALL and E_STRICT

As you can see in the table above, in PHP5 In versions 3 and below, e_ The value of all is 30719 because PHP5 E of 3_ All does not contain E_STRICT level error, but in PHP5 4, E_ALL has defaulted to E_STRICT is included

This is because of the PHP version upgrade process, E_STRICT is a strict mode. For example, we all know that static methods in classes should be static only, and non static methods need to instantiate classes. Later, PHP also supports the use of: a static way to call a non static method, but at this time, if we start a strict mode E_STRICT; Will result in an E_STRICT level error

The following code, in PHP5 There is no problem running in 3, but in PHP5 An error will be reported in 4

ini_set("display_errors", true);
class a {
    public function test() {
        echo 1111;

The above code, if in PHP5 3, then there is no problem if it is in PHP5 4 and above, the following error will be reported

Strict standards: Non-static method a::test() should not be called statically in ....

So you will see error in some lower versions of php code_ Reporting (e_all | e_strict)

3.5 principle of error level in PHP

The error level of php is essentially stored in bitmap method. Each bit of binary is used to represent a state. For example, a byte has 8 bits. By distinguishing 01 from each bit of the 8 big, it can represent 8 states. Back to php, let's disassemble the error mode of php and look at the following pictures ↓↓

We modify the value of errorlevel, that is, modify the state of the corresponding bit.

3.5.1 or operation mode to accumulate different error levels

The rule of or operation is that one party is 1, the result is 1, both are 0, and the result is 0

Here we set only E_ERROR and e_ Note these two levels of errors

ini_set("display_errors", true);
$errorLevel = E_ERROR | E_NOTICE;
// Print the value of $errorLevle
echo $errorLevel; // 9

In the above code, we set the error level value to 9, and php will only report E_ERROR and e_ Note these two levels of errors will be masked. What is the internal mechanism of php? Let's take a look

    E_ERROR Value of = 1; The corresponding binary is 0000 0001
    E_NOTICE Value of = 8; The corresponding binary is 0000 1000
         After the bitwise OR operation of these two values---------
                            The result is 0000 1001
                            The corresponding number converted to hexadecimal is 9

    In php, to determine whether it is the corresponding error level, you only need to use [corresponding error level] & [set error level]
    Let's assume that php has a note level error during operation, and judge whether the error level is enabled
    if (E_NOTICE & $errorLevel) {
        // The note level is enabled to handle errors
    In the above code, just use bitwise&, You can judge
    E_NOTICE    Value of = 8; The corresponding binary is 0000 1000
    $errorLevel Value of = 9; The corresponding binary is 0000 1001
                      The result of the operation is 80000 1000

    Then if you use E_WARNING To judge, please see below
    E_WARNING   Value of = 2; The corresponding binary is 0000 0010
    $errorLevel Value of = 9; The corresponding binary is 0000 1001
                      The result after the operation is 0 0000 0000
    As you can see, the result is 0, which does not match the current error level

Through the above description and the above picture, it can be found that it is essentially to modify the state of the corresponding bit. When using, different operations are carried out by judging the state of the bit

3.5.2 exclude a state by XOR

Lazy, write less, you can refer to or calculate, which is essentially the same

The XOR rule is: the same is 0 and the difference is 1

// Use E_ALL, and E is excluded_ Note and E_WARNING, it can be written like this
$errorLevel = E_ALL ^ E_NOTICE ^ E_WARNING;
    What is their calculation process? Let's have a look
    E_ALL    Value of = 32767; The corresponding binary is 1111 1111 1111 1111
    E_NOTICE Value of = 8;     The corresponding binary is 0000 1000
                                 The result is 1111 1111 1111 0111

    Looking at the above results, is it found that the state of the binary bit corresponding to 8 has changed to 0, and the other bit states have not changed, 
    So it's equivalent to excluding 8, that is E_NOTICE, Let's use this result to compare with E_WARNING XOR

    The result of the previous step is                       1111 1111 1111 1111
    E_WARNING Value of = 2;                 0000 0000 0000 0010
                                 The result is 1111 1111 1111 0101

    You can see, put E_WARNING The corresponding status is also set to 0

3.5.3 take the inverse first and then connect with&

The result is XOR. I won't say more here



Write at the end

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Keywords: PHP Apache

Added by KirstyScott on Thu, 06 Jan 2022 14:24:08 +0200