When executing prepared statements with PHP’s MySQLi extension, mysqli_stmt::$error_list is an essential debugging tool. Unlike $stmt->error which only returns the last error, this property provides an array containing all error messages. When multiple errors occur during a single execution or preparation, it becomes especially critical.

ctype_upper() is a commonly used character classification function that checks whether all characters in a string are uppercase letters. Its syntax is very simple:

In PHP development, loading third-party libraries is a common task. To ensure external libraries are correctly included and used, it is often necessary to set PHP’s include path. The set_include_path() function is one of the tools used to set or modify this path. This article will guide you on how to properly use the set_include_path() function and share practical tips to help you load third-party libraries more efficiently.

The strftime function is used to format dates and times, returning a string based on a specified format. Its basic syntax is as follows:

In PHP development, checking whether a user is logged in is a common requirement. Typically, this is done by verifying the user's session or checking their login status. Beyond traditional session methods, PHP offers functions that can indirectly help determine if a user is logged in. This article explains how to use the getmyuid() function as a simple and effective way to check a user's login status.

Converting between degrees and radians is a common operation, especially in mathematical calculations, graphics rendering, and physics simulations.

When working with large XML files, performance optimization has always been a major concern for developers. In particular, when using xml_parser_create_ns in PHP to parse XML files with namespaces, improving efficiency and reducing memory consumption becomes a critical challenge. This article explores several key techniques to boost performance, helping you parse large XML files more effectively.

The basic syntax of the mb_encode_numericentity function is as follows:

One of the most common reasons is incorrect file or directory permission settings. Write permissions for files or directories are usually managed by the operating system’s file system. If the permissions are not set to writable, the is_writable function will return false.

In PHP development, managing HTTP response headers is a common task. Combining the header() and headers_sent() functions effectively can prevent errors from duplicate header sends and improve both program robustness and user experience.

This document demonstrates how to effectively use mb_encode_numericentity together with htmlentities for handling character encoding in PHP, ensuring multibyte characters are correctly processed without data loss or corruption.

convert_cyr_string is a PHP function used to convert strings from one Cyrillic character set (such as KOI8-R, Windows-1251, etc.) to another. Its basic usage is as follows:

When performing precise mathematical operations in PHP, conventional floating-point calculations often suffer from precision loss. This is particularly critical when dealing with money, profit, and other financial calculations. PHP offers a powerful math extension library—BCMath (Big Numbers)—specifically designed to handle large numbers and high-precision operations. The bcsub and bcmul functions in the BCMath library can be used together to ensure high precision when calculating profits.

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