GLFENCESYNC(3G)

✨ glFenceSync: the fence-sync bestie manual ✨

Okay bestie, this is the GLFENCESYNC(3G) page — yes, the header has a [FIXME: manual] placeholder, but the vibe is immaculate. Let's get into it.

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🌸 NAME 🌸

glFenceSync — create a new sync object and insert it into the GL command stream. Periodt.

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💻 C SPECIFICATION 💻

GLsync glFenceSync(GLenum condition, GLbitfield flags);

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🎀 PARAMETERS 🎀

• condition — specifies the condition that must be met to set the sync object's state to signaled. condition must be GL_SYNC_GPU_COMMANDS_COMPLETE.
• flags — 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.[1]

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🦋 DESCRIPTION 🦋

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

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. Read that twice, bestie — it's giving "order matters."

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📝 NOTES 📝

glFenceSync is only supported if the GL version is 3.2 or greater, or if the ARB_sync extension is supported.

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💀 ERRORS 💀

• 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. Not the zero we want, bestie.

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👑 VERSION SUPPORT 👑

Function / Feature Name: glFenceSync. OpenGL Version check, no cap:

• OpenGL 2.0: -
• OpenGL 2.1: -
• OpenGL 3.0: -
• OpenGL 3.1: -
• OpenGL 3.2: ✔
• OpenGL 3.3: ✔
• OpenGL 4.0: ✔
• OpenGL 4.1: ✔
• OpenGL 4.2: ✔
• OpenGL 4.3: ✔
• OpenGL 4.4: ✔
• OpenGL 4.5: ✔

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🫶 SEE ALSO 🫶

glDeleteSync(), glGetSync(), glWaitSync(), glClientWaitSync()

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📜 COPYRIGHT 📜

Copyright © 2010-2014 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. http://opencontent.org/openpub/.

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📜 COPYRIGHT 📜

Copyright © 2010-2014 Khronos Group

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📝 NOTES 📝

1. flags is a placeholder for anticipated future extensions of fence sync object capabilities.

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💖 Cute sign-off: source note says [FIXME: source], dated 08/09/2021, and this whole thing is the GLFENCESYNC(3G) manual. Bye bestie — go fence those syncs! 💖