Fix cudaErrorStreamCaptureUnjoined: Streams Not Joined

Overview

cudaErrorStreamCaptureUnjoined occurs when forked streams not joined before EndCapture.

Error Messages

CUDA error: stream capture unjoined
cudaErrorStreamCaptureUnjoined

Common Causes

• •Forgot to join
• •Missing stream wait
• •Event not recorded

Solutions

cudaEventRecord(e, s2);
cudaStreamWaitEvent(s1, e);  // Join
cudaStreamEndCapture(s1, &graph);

Prevention Tips

• ✓Track forked streams
• ✓Always join before end

Code Examples

Before (Problematic)

Unjoined.

cudaStreamWaitEvent(s2, e);  // Fork
kernel<<<g,b,0,s2>>>();
cudaStreamEndCapture(s1, &g);  // s2 not joined!

After (Fixed)

All joined.

cudaEventRecord(e, s2); cudaStreamWaitEvent(s1, e);  // Join
cudaStreamEndCapture(s1, &g);

Frequently Asked Questions

Related Errors

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