When Windows cannot detect a second monitor, first check whether the physical connection is normal, including power supply, cable plug-in and interface compatibility, and try to replace the cable or adapter; secondly, update or reinstall the graphics card driver through the Device Manager, and roll back the driver version if necessary; then manually click "Detection" in the display settings to identify the monitor to confirm whether it is correctly identified by the system; finally check whether the monitor input source is switched to the corresponding interface, and confirm whether the graphics card output port connected to the cable is correct. Following the above steps to check in turn, most dual-screen recognition problems can usually be solved.

In C, there are three main ways to pass functions as parameters: using function pointers, std::function and Lambda expressions, and template generics. 1. Function pointers are the most basic method, suitable for simple scenarios or C interface compatible, but poor readability; 2. Std::function combined with Lambda expressions is a recommended method in modern C, supporting a variety of callable objects and being type-safe; 3. Template generic methods are the most flexible, suitable for library code or general logic, but may increase the compilation time and code volume. Lambdas that capture the context must be passed through std::function or template and cannot be converted directly into function pointers.

In C, the POD (PlainOldData) type refers to a type with a simple structure and compatible with C language data processing. It needs to meet two conditions: it has ordinary copy semantics, which can be copied by memcpy; it has a standard layout and the memory structure is predictable. Specific requirements include: all non-static members are public, no user-defined constructors or destructors, no virtual functions or base classes, and all non-static members themselves are PODs. For example structPoint{intx;inty;} is POD. Its uses include binary I/O, C interoperability, performance optimization, etc. You can check whether the type is POD through std::is_pod, but it is recommended to use std::is_trivia after C 11.

The key steps to install PHP on Windows include: 1. Download the appropriate PHP version and decompress it. It is recommended to use ThreadSafe version with Apache or NonThreadSafe version with Nginx; 2. Configure the php.ini file and rename php.ini-development or php.ini-production to php.ini; 3. Add the PHP path to the system environment variable Path for command line use; 4. Test whether PHP is installed successfully, execute php-v through the command line and run the built-in server to test the parsing capabilities; 5. If you use Apache, you need to configure P in httpd.conf

In C, the mutable keyword is used to allow the object to be modified, even if the object is declared as const. Its core purpose is to maintain the logical constants of the object while allowing internal state changes, which are commonly found in cache, debug counters and thread synchronization primitives. When using it, mutable must be placed before the data member in the class definition, and it only applies to data members rather than global or local variables. In best practice, abuse should be avoided, concurrent synchronization should be paid attention to, and external behavior should be ensured. For example, std::shared_ptr uses mutable to manage reference counting to achieve thread safety and const correctness.

MemoryalignmentinC referstoplacingdataatspecificmemoryaddressesthataremultiplesofavalue,typicallythesizeofthedatatype,whichimprovesperformanceandcorrectness.1.Itensuresdatatypeslikeintegersordoublesstartataddressesdivisiblebytheiralignmentrequiremen

There are three effective ways to generate UUIDs or GUIDs in C: 1. Use the Boost library, which provides multi-version support and is simple to interface; 2. Manually generate Version4UUIDs suitable for simple needs; 3. Use platform-specific APIs (such as Windows' CoCreateGuid), without third-party dependencies. Boost is suitable for most modern projects, manual implementation is suitable for lightweight scenarios, and platform API is suitable for enterprise environments.

C isusedforbuildinghigh-performanceapplicationswherecontroloversystemresourcesandefficiencyarecritical.Itiswidelyadoptedingamedevelopment,poweringengineslikeUnrealandenablingfine-tunedperformanceforcomplexgraphicsandphysicshandling.Itisalsousedinsys