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Core in version 4.6
Core since version 3.2
Core ARB extension ARB_sync

glFenceSync: create a new sync object and insert it into the GL command stream

Function Definition

 GLsync glFenceSync(GLenum condition​, GLbitfield flags​);
Specifies the condition that must be met to set the sync object's state to signaled. condition​ must be GL_SYNC_GPU_COMMANDS_COMPLETE.
Specifies a bitwise combination of flags controlling the behavior of the sync object. No flags are presently defined for this operation and flags​ must be zero.(Note: flags​ is a placeholder for anticipated future extensions of fence sync object capabilities.)


glFenceSync creates a new fence sync object, inserts a fence command into the GL command stream and associates it with that sync object, and returns a non-zero name corresponding to the sync object.

When the specified condition​ of the sync object is satisfied by the fence command, the sync object is signaled by the GL, causing any glWaitSync, glClientWaitSync commands blocking in sync​ to unblock. No other state is affected by glFenceSync or by the execution of the associated fence command.

condition​ must be GL_SYNC_GPU_COMMANDS_COMPLETE. This condition is satisfied by completion of the fence command corresponding to the sync object and all preceding commands in the same command stream. The sync object will not be signaled until all effects from these commands on GL client and server state and the framebuffer are fully realized. Note that completion of the fence command occurs once the state of the corresponding sync object has been changed, but commands waiting on that sync object may not be unblocked until after the fence command completes.




GL_INVALID_ENUM is generated if condition​ is not GL_SYNC_GPU_COMMANDS_COMPLETE.

GL_INVALID_VALUE is generated if flags​ is not zero.

Additionally, if glFenceSync fails, it will return zero.

See Also

glDeleteSync, glGetSync, glIsSync, glWaitSync, glClientWaitSync


Copyright © 2010 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999.