The C Standard, 7.28.5.6 paragraph 2 [ISO/IEC 9899:2024], states that a thread shall not be joined once it was previously joined or detached.
The termination of the other thread synchronizes with the completion of the thrd_join function. The thread identified by thr shall not have been previously detached or joined with another thread.
Similarly, subclause 7.28.5.3 paragraph 2 [ISO/IEC 9899:2024], states that a thread shall not be detached once it was previously joined or detached.
The thrd_detach function tells the operating system to dispose of any resources allocated to the thread identified by thr when that thread terminates. The thread identified by thr shall not have been previously detached or joined with another thread.
Violating either of these subclauses results in undefined behavior 211.
Noncompliant Code Example
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Joining or detaching a previously joined or detached thread is undefined behavior 211.
Rule | Severity | Likelihood | Detectable | RepairableRemediation Cost | Priority | Level |
|---|---|---|---|---|---|---|
CON39-C | Low | Likely | No | MediumNo | P6P3 | L2L3 |
Automated Detection
Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Astrée |
| Supported, but no explicit checker | |||||||
| CodeSonar |
| CONCURRENCY.TNJ | Thread is not Joinable | ||||||
| Cppcheck Premium |
| premium-cert-con39-cFully implemented | |||||||
| Helix QAC |
| C1776 | |||||||
| Parasoft C/C++test |
| CERT_C-CON39-a | Do not join or detach a thread that was previously joined or detached | ||||||
| Polyspace Bug Finder |
| CERT C: Rule CON39-C | Checks for join or detach of a joined or detached thread (rule fully covered) |
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