GetStdHandle

GetStdHandle is a Windows API function that retrieves a handle to one of the process’s standard devices: input, output, or error. It is declared in Windows.h and implemented in kernel32.dll. The function is commonly used in low-level Windows I/O scenarios to obtain a handle that can be used with native I/O functions or console APIs.

The parameter nStdHandle selects which device to return. It accepts STD_INPUT_HANDLE (-10), STD_OUTPUT_HANDLE (-11), or STD_ERROR_HANDLE (-12). The return value is a HANDLE. On success, the handle may be a real system handle to the device or a pseudo handle that represents the standard device. If the process has no associated console, GetStdHandle can return a pseudo handle. Pseudo handles are valid for certain console I/O operations but are not interchangeable with real handles in all API calls. If the function fails, the return value is INVALID_HANDLE_VALUE and GetLastError provides the specific error code.

Usage considerations include checking the return value before using the handle and recognizing that pseudo handles have limitations. The obtained handle can be used with low-level I/O functions such as ReadFile and WriteFile, or with console APIs that accept a HANDLE. To replace or redirect standard handles, SetStdHandle can be used, or a console can be allocated with AllocConsole in GUI applications that require a console. GetStdHandle is a common starting point when a program needs to interact with the process’s conventional input or output streams at the Windows API level.