PHP | xml_error_string() Function

Pre-requisite: XML Basics
The xml_error_string() function is an inbuilt function in PHP which returns the XML parser error description for generated error code.

Syntax:

string xml_error_string( int $error_code)

Parameters: This function accepts single parameter $error_code which is required. It specifies an XML parser error code which is generated from the xml_get_error_code() function.

Return Values: This function returns the XML parser error description for specified error code generated from xml_get_error_code() on success and False on failure.

Note: This function is available for PHP 4.0.0 and newer version.

Below programs illustrate the xml_error_string() function in PHP:
gfg.xml file:

XML

<?xml version="1.0" encoding="utf-8"?>
<user>
    <username> user123 </username>
    <name> firstname lastname </name>
    <phone> +91-9876543210 </phone>
    <detail> I am John Doe. Live in Kolkata, India. </detail>
</users>

Program 1:

PHP

<?php

// Invalid XML file
$xml_file= 'gfg.xml';

// XML parser initialization
$xml_parser = xml_parser_create();

// Opening the file in read mode
$file_pointer = fopen($xml_file, 'r');

// Reading data from the file stream
while ($xml_data = fread($file_pointer, 4096)) {

    // Parsing the data chunk
    if (!xml_parse($xml_parser, $xml_data, feof($file_pointer))) {

        // Display error
        die( print "ERROR: " .

            // Error string
            xml_error_string(xml_get_error_code($xml_parser)) .

            "<br>Error Code: " .

            // Error code
            xml_get_error_code($xml_parser) .

            "<br>Line: " .

            // Line number where the error occurred
            xml_get_current_line_number($xml_parser) .

            "<br>Column: " .

            // Column number where the error occurred
            xml_get_current_column_number($xml_parser) .

            "<br>Byte Index: " .

            // Byte index where the current byte occurred
            xml_get_current_byte_index($xml_parser) . "<br>"
        );
    }
}

// Free to xml parser
xml_parser_free($xml_parser);

?>

Output:

ERROR: Mismatched tag
Error Code: 76
Line: 7
Column: 13
Byte Index: 208

geeks.xml file:

XML

<?xml version="1.0 encoding="utf-8"?>
<user>
    <username> user123 </username>
    <name> firstname lastname </name>
    <phone> +91-9876543210 </phone>
    <detail> I am John Doe. Live in Kolkata, India. </detail>
</user>

Program 2:

PHP

<?php

// Invalid XML file
$xml_file= 'geeks.xml';

// XML parser initialization
$xml_parser = xml_parser_create();

// Opening the file in read mode
$file_pointer = fopen($xml_file, 'r');

// Reading data from the file stream
while ($xml_data = fread($file_pointer, 4096)) {

    // Parsing the data chunk
    if (!xml_parse($xml_parser, $xml_data, feof($file_pointer))) {

        // Display error
        die( print "ERROR: " .

            // Error string
            xml_error_string(xml_get_error_code($xml_parser)) .

            "<br>Error Code: " .

            // Error code
            xml_get_error_code($xml_parser) .

            "<br>Line: " .

            // Line number where the error occurred
            xml_get_current_line_number($xml_parser) .

            "<br>Column: " .

            // Column number where the error occurred
            xml_get_current_column_number($xml_parser) .

            "<br>Byte Index: " .

            // Byte index where the current byte occurred
            xml_get_current_byte_index($xml_parser) . "<br>"
        );
    }
}

// Free to xml parser
xml_parser_free($xml_parser);

?>

Output:

ERROR: String not closed expecting " or '
Error Code: 34
Line: 1
Column: 36
Byte Index: 37

Reference: https://www.php.net/manual/en/function.xml-error-string.php