|`_loaddll`|[LoadLibrary](https://msdn.microsoft.com/library/windows/desktop/ms684175\(v=vs.85\).aspx), [LoadLibraryEx](/windows/desktop/api/libloaderapi/nf-libloaderapi-loadlibraryexa), or [LoadPackagedLibrary](/windows/desktop/api/winbase/nf-winbase-loadpackagedlibrary)|

|`_unloaddll`|[FreeLibrary](https://msdn.microsoft.com/library/windows/desktop/ms683152\(v=vs.85\).aspx)|

|`_getdllprocaddr`|[GetProcAddress](../build/getprocaddress.md)|

|`_beep`|[Beep](https://msdn.microsoft.com/library/windows/desktop/ms679277\(v=vs.85\).aspx)|

|`_sleep`|[Sleep](/windows/desktop/api/synchapi/nf-synchapi-sleep)|

|`_getsystime`|[GetLocalTime](https://msdn.microsoft.com/library/windows/desktop/ms724338\(v=vs.85\).aspx)|

Terminates the calling process. The **exit** function terminates it after cleanup; **_exit** and **_Exit** terminate it immediately.

Before Visual C++ 2010, each call to **operator+** allocates and returns a new temporary `string` object (an rvalue). **operator+** cannot append one string to the other because it does not know whether the source strings are lvalues or rvalues. If the source strings are both lvalues, they might be referenced elsewhere in the program and therefore must not be modified. By using rvalue references, **operator+** can be modified to take rvalues, which cannot be referenced elsewhere in the program. Therefore, **operator+** can now append one string to another. This can significantly reduce the number of dynamic memory allocations that the `string` class must perform. For more information about the `string` class, see [basic_string Class](../standard-library/basic-string-class.md).

To better understand move semantics, consider the example of inserting an element into a `vector` object. If the capacity of the `vector` object is exceeded, the `vector` object must reallocate memory for its elements and then copy each element to another memory location to make room for the inserted element. When an insertion operation copies an element, it creates a new element, calls the copy constructor to copy the data from the previous element to the new element, and then destroys the previous element. Move semantics enables you to move objects directly without having to perform expensive memory allocation and copy operations.

- [Microsoft Help and Support](https://support.microsoft.com/)

This error can be caused by disk error.

1. If you are compiling on a 64-bit platform, use the 64-bit compiler toolset. For information, see [How to: Enable a 64-Bit Visual C++ Toolset on the Command Line](../../build/how-to-enable-a-64-bit-visual-cpp-toolset-on-the-command-line.md).

1. Increase the size of the Windows swap-file.

If the file is locked by an anti-virus program, you can fix this issue by excluding your build output directories from automatic scanning by the anti-virus program. Anti-virus scanners are often triggered by the creation of new files in the file system, and they hold locks on the files while the scan proceeds. Consult your anti-virus program documentation for details about how to exclude specific directories from scanning.

If your executable can’t be overwritten by the build process, it may be locked by File Explorer. If the **Application Experience** service has been disabled, File Explorer may hold on to an executable file handle lock for an extended time. To fix this issue, run **services.msc** and then open the **Properties** dialog box for the **Application Experience** service. Change the **Startup type** from **Disabled** to **Manual**.

For additional information, see:

- [Adhering to System Policy Settings](https://msdn.microsoft.com/library/aa372139), the section on "Run only allowed Windows applications".