Open System Services System Calls Reference Manual (G06.25+, H06.03+)

System Functions (f - i) fork(2)
• Process access ID (PAID)
• Security group list
• Job ancestor or GMOM
• Unread system message index count (PCBMCNT)
This attribute assignment is different from the assignment made when creating a new
process with Guardian procedures.
• Outstanding incoming and outgoing message limits
This attribute assignment is different from the assignment made when creating a new
process with Guardian procedures.
• Login, remote login, and saveabend flags
• File creation mask
The Guardian attributes of the child process differ from those of the parent process in the follow-
ing ways:
• Segments created or shared using Guardian procedures such as
SEGMENT_ALLOCATE_ are not inherited.
• The child process does not inherit the parent process extended swap file (if any). For a
G-series TNS process or an accelerated process, the extended data segment is managed
by the Kernel Managed Storage Facility (KMSF).
• The child’s process name is system-generated if the RUNNAMED option is set in the
program file. Otherwise the process is unnamed.
• The DEFINEs inheritance for the child depends on the parent’s DEFINE mode.
• The process identification number (PIN) of the child process is unrelated to that of the
parent process. The PIN of the child process is unrestricted if both of the following are
true:
— The HIGHPIN flag is set in the program file and any user library file.
— The PIN of the parent process was unrestricted.
If the PIN of the child process is restricted, then the PIN is in the range 0 through 254.
• The MOM field for the child process is set to 0 (zero).
• System debugger selection for the child process is based on Inspect mode and OSS read
access rights on the program file.
• Code breakpoints and memory breakpoints are not inherited.
For detailed information about Guardian process attributes, see the PROCESS_LAUNCH_ pro-
cedure in the Guardian Procedure Calls Reference Manual.
Sharing Guardian Files
After a successful call to the fork() function, the initial position within an EDIT file (file code
101) in the Guardian file system (a file in /G) that was opened by a call to the OSS open() func-
tion is the same for both the parent and child processes. However, the position is not shared; that
is, changing the position used by one process does not change the position used by the other pro-
cess.
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