Guardian Procedure Calls Reference Manual

caller. When it is created in a nowait manner, its identification is returned in a system message
sent to the caller's $RECEIVE file.
• You can obtain a level of fault tolerance in OSS processes by calling PROCESS_SPAWN_ to
create OSS processes from a monitor implemented as a Guardian process pair. The monitor
checks that the created OSS process continues to run and restarts it if there is a failure. For
more information on writing fault-tolerant programs, see the Guardian Programmer's Guide.
• You can call PROCESS_SPAWN_ from a Guardian process, a 32-bit OSS process, or in a
mixed-mode programming environment from a 64-bit OSS process.
• The caller of PROCESS_SPAWN_ becomes the Guardian parent of the new OSS process.
• Because the caller of PROCESS_SPAWN_ is the Guardian parent of the new OSS process,
when the new process is terminated, it receives a process deletion system message (-101)
through its $RECEIVE file rather than an OSS SIGCHLD signal. The caller also receives this
message (with a different completion code) when the child process calls one of the OSS exec
set of functions and migrates to a new process handle. For more information on the process
deletion message and its completion codes, see the Guardian Procedure Errors and Messages
Manual.
• The new process does not have an OSS caller; instead it is considered to be an OSS orphan
process with a caller process ID of 1.
• OSS file opens in the calling process are not propagated to the new process. The file opens
must be specified explicitly in the fdinfo parameter.
• The created OSS process is always the leader of its own session.
• The calling process is not required to be compliant with the Common Run-Time Environment.
• PROCESS_SPAWN_ can create a process on local system or on a remote system.
• These following OSS attributes are passed, unchanged, from the caller to the new OSS process,
whether the caller is an OSS process or a Guardian process:
◦ Real, effective, and saved OSS user ID
◦ Real, effective, and saved group ID
◦ Group list
◦ Login name
◦ Current working directory
◦ Maximum file size
◦ Default OSS file security
No other OSS process attribute is inherited by the new process.
Beginning with the H06.25 and J06.14 RVUs, the PROCESS_SPAWN_ procedure can create an
OSS backup process. This feature provides the NonStop characteristics of process pairs in the
OSS environment.
NOTE: Although it is possible to create an OSS process pair on older RVUs, the feature is
unsupported prior to the T9050 SPRs that participate in the H06.25 and J06.14 RVUs.
For more information on creating an OSS process and for details on the parameters to this
procedure, see the tdm_spawn() function reference page either online or in the Open System
Services System Calls Reference Manual.
1096 Guardian Procedure Calls (P)