glClientWaitSync

glClientWaitSync: man4/glClientWaitSync.xml

glClientWaitSync causes the client to block and wait for the sync object specified by sync to become signaled. If sync is signaled when glClientWaitSync is called, glClientWaitSync returns immediately, otherwise it will block and wait for up to timeout nanoseconds for sync to become signaled. The return value is one of four status values:

1. GL_ALREADY_SIGNALED indicates that sync was signaled at the time that glClientWaitSync was called.
2. GL_TIMEOUT_EXPIRED indicates that at least timeout nanoseconds passed and sync did not become signaled.
3. GL_CONDITION_SATISFIED indicates that sync was signaled before the timeout expired.
4. GL_WAIT_FAILED indicates that an error occurred. Additionally, an OpenGL error will be generated.

glClientWaitSync is available only if the GL version is 3.2 or greater.