Bit 0 |
Allocate this memory as shared. |
Bit 1 |
Reserved. Must be set to zero. |
Bit 2 |
Allocate this memory independently from any calling program. If bit 3 is set it will be freed automatically when the calling thread ends. If bit 3 is unset it will be freed when the run-unit ends. |
Bit 3 |
Allocate this memory as thread local. If bit 2 is unset and there is a direct or indirect (in a mixed language environment) calling COBOL program, it will be freed when the calling program is canceled or the thread ends - whichever comes first. |
Bits 4-31 |
Reserved. Must be set to 0. |
Comments:
The memory allocated is not initialized to any value.
Updates to any shared memory allocated to this function are not serialized or protected by the run-time system; you should use semaphores to maintain the integrity of the data.
If the memory has been allocated by a thread, it is freed when the calling thread terminates.
The maximum size of nonshared memory is restricted only by your operating system (unless the -l run-time switch is set).
The maximum size of shared memory is restricted by the operating system and the run-time system. The run-time tunable, shared_memory_segment_size, can be used to set the maximum size.
Bit 1 and bit 2 or bit 3 are mutually exclusive. This is checked and error 181 returned otherwise. If there is no calling program (directly or indirectly in a mixed language environment) bit 2 is ignored.
If bit 2 is not set all standard memory allocated by CBL_ALLOC_MEM is freed when the program that allocated it is canceled (logically or physically), if there is a COBOL program that is directly or indirectly the caller.