System Services

The system services functions give applications access to the resources of the computer and the features of the underlying operating system, such as memory, file systems, devices, processes, and threads. An application uses these functions to manage and monitor the resources it needs to complete its work. For example, an application uses memory management functions to allocate and free memory. Process management and synchronization functions start and coordinate the operation of multiple applications or multiple threads of execution within a single application.

The file system functions provide access to files, directories, and input and output (I/O) devices. These functions give applications access to files and directories on disks and other the storage devices on a specified computer and on computers in a network. The file I/O functions support a variety of file systems, including the FAT file system, the CD-ROM file system (CDFS), and NTFS.

Applications can share code or information with other applications. For example, they can make useful procedures available to all applications by placing these procedures in DLLs. Applications access these procedures by using DLL functions to load the libraries and retrieve the addresses of the procedures. Communications functions read from and write to communications ports as well as control the operating modes of these ports. For interprocess communication (IPC), there are pipes and mailslots.

Registry and initialization functions let applications store application-specific information in system files so that new instances of the application or even other applications can retrieve and use the information.

For more information, see the following overviews.



Build date: 3/25/2010