Security system values: Allow use of shared or mapped memory with write capability
The Allow use of shared or mapped memory with write capability system value is also known as QSHRMEMCTL. You can use this system value to specify whether users are allowed to use shared or mapped memory with write capability.
| Quick reference | |
|---|---|
| Location | From IBM® Navigator for i, select . Right-click on Security and click Properties, then select the Shared Memory tab. |
| Special authority | All object (*ALLOBJ) and security administrator (*SECADM). |
| Default value | Selected. Shared or mapped memory with write capability is allowed. |
| Changes take effect | Immediately. |
| Lockable | Yes. |
What can I do with this system value?
You can specify whether users are allowed (1) or are not allowed (0) to use shared memory or mapped memory stream files. By allowing this option, users can use shared-memory APIs (for example, shmat() - Shared Memory Attach API), and can use mapped memory objects that have stream files (for example, mmap() - Memory Map a File API). Allowing access to shared memory and mapped memory stream files is recommended for environments where pointers can be shared among programs, which might be running in different jobs. However, this setting is not recommended for environments with higher security requirements.