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

glWaitSync: instruct the GL server to block until the specified sync object becomes signaled

Function Definition

 void glWaitSync(GLsync sync​, GLbitfield flags​, GLuint64 timeout​);
Specifies the sync object whose status to wait on.
A bitfield controlling the command flushing behavior. flags​ may be zero.
Specifies the timeout that the server should wait before continuing. timeout​ must be GL_TIMEOUT_IGNORED.


glWaitSync causes the GL server to block and wait until sync​ becomes signaled. sync​ is the name of an existing sync object upon which to wait. flags​ and timeout​ are currently not used and must be set to zero and the special value GL_TIMEOUT_IGNORED, respectively(Note: flags​ and timeout​ are placeholders for anticipated future extensions of sync object capabilities. They must have these reserved values in order that existing code calling glWaitSync operate properly in the presence of such extensions.). glWaitSync will always wait no longer than an implementation-dependent timeout. The duration of this timeout in nanoseconds may be queried by calling glGet with the parameter GL_MAX_SERVER_WAIT_TIMEOUT. There is currently no way to determine whether glWaitSync unblocked because the timeout expired or because the sync object being waited on was signaled.

If an error occurs, glWaitSync does not cause the GL server to block.


glWaitSync is available only if the GL version is 3.2 or higher.


GL_INVALID_VALUE is generated if sync​ is not the name of a sync object.

GL_INVALID_VALUE is generated if flags​ is not zero.

GL_INVALID_VALUE is generated if timeout​ is not GL_TIMEOUT_IGNORED.

See Also

glFenceSync, 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.