## Presentation Device Driver Reference for OS/2

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### GreUnlockDevice - Syntax

Simulation support:

None. This function is mandatory for all drivers.

Description:

GreUnlockDevice allows all pending screen input or output operations blocked by GreLockDevice to continue.

This function must be supported by all presentation drivers. For hardcopy devices, the hardcopy driver need do nothing except return TRUE (Successful ). GreUnlockDevice is used to enable another process to access a resource ( device context) that had been previously locked to prevent simultaneous update.

    #define INCL_GRE_DEVMISC3

    #include <os2.h>

    HDC      hdc;        /*  Device context handle. */

    PVOID    pInstance;  /*  Pointer to instance data. */

    ULONG    lFunction;  /*  High-order WORD=flags; low-order WORD=NGreUnlockDevice. */

    BOOL     rc;         /*  Return codes. */

    rc = GreUnlockDevice(hdc, pInstance, lFunction);