Locks the working page's framebuffer
Syntax
Usage
ScreenLock
Description
The
ScreenLock function locks the current work page framebuffer for direct memory access.
Framebuffer memory may be freely accessed (read/write) and primitive graphics statements may be called during the time a screen is locked.
The screen remains locked until the use of
ScreenUnlock statement.
ScreenLock must only be used on a screen that is unlocked - or in other words, a screen that is not already locked with
ScreenLock.
It is strongly recommended that the lock on a page be held for as short a time as possible. Only screen drawing should occur while the screen is locked, input/output and waiting must be avoided.
Once the page is locked, the screen contents will not be automatically updated until the page is unlocked with the
ScreenUnlock statement. If the work page is the same as the visible page, any modifications to the page memory while locked will not become visible until
ScreenUnlock is called.
Example
Dialect Differences
- Not available in the -lang qb dialect unless referenced with the alias __Screenlock.
Differences from QB
See also