Specifies whether users are allowed to use shared memory or mapped memory stream files or not. (QSHRMEMCTL)
Allow use of shared or mapped memory with write capability, also known as QSHRMEMCTL, is a member of the security category of i5/OS™ system values. You can use this system value to specify whether shared or mapped memory with write capability can be used or not. To learn more, keep reading.
| Quick reference | |
|---|---|
| Location | In iSeries™ Navigator, select your system, |
| 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 Lock function of security-related system values (Click for details) |
What can I do with this system value?
You may specify whether users are allowed (1) or are not allowed (0) to use shared memory or mapped memory stream files. You may select whether or not to allow access to shared memory, or use 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 may be shared among programs, which may be running in different jobs. However, this setting is not recommended for environments with higher security requirements.
Where can I get more information about this system value?
To learn more, go to the security system values overview topic. If you are looking for a specific system value or category of system values, try using the i5/OS system value finder.