Changes selected metadata such as permissions on a System V message queue.
What It Does and When to Use It
Set queue permissions with the expected metadata key. A producer publishes work, a consumer executes it, and the broker or scheduler controls delivery and retries.
Requirements, Inputs and Expected Behavior
Confirm the runtime, extension, environment variables, and permissions before running the examples in production. Ownership and permissions depend on OS capabilities; invalid keys raise warnings.
Example 1: Basic Operation
Set queue permissions with the expected metadata key.
<?php
$queue = msg_get_queue(0x13330, 0600);
if (!msg_set_queue($queue, ['msg_perm.mode' => 0600])) {
throw new RuntimeException('Permission update failed');
}Example 2: Behavior and Validation
Read back the permission bits after a change.
<?php
$queue = msg_get_queue(0x13331, 0600);
$before = msg_stat_queue($queue);
msg_set_queue($queue, ['msg_perm.mode' => 0640]);
$after = msg_stat_queue($queue);
echo decoct($before['msg_perm.mode'] & 0777), ' -> ', decoct($after['msg_perm.mode'] & 0777);Practical Example: Application Use
Keep a temporary queue private and clean it up.
<?php
$queue = msg_get_queue(0x13332, 0600);
try { msg_set_queue($queue, ['msg_perm.mode' => 0600]); }
finally { msg_remove_queue($queue); }Important Behavior and Edge Cases
The second example highlights: Read back the permission bits after a change. The practical example adds: Keep a temporary queue private and clean it up.
Comparison with Related Approaches
| Approach | What changes |
|---|---|
| Producer, consumer and scheduler | A producer publishes work, a consumer executes it, and the broker or scheduler controls delivery and retries. |
| Choosing safely | Acknowledge completed work and use idempotency to make retries safe. |
Common Beginner Mistakes
| Mistake | Correct approach |
|---|---|
| Acknowledging a job before it finishes | Mark delivery successful only after durable processing succeeds. |
| Treating retries as harmless | Use idempotency keys and a bounded retry policy with dead-letter handling. |
| Skipping operational constraints | Ownership and permissions depend on OS capabilities; invalid keys raise warnings. |
Key Takeaways
- Changes selected metadata such as permissions on a System V message queue.
- Keep a temporary queue private and clean it up.
- Acknowledge completed work and use idempotency to make retries safe.