Language Environment process control block

Each process is represented by a process control block (PCB). All process resources are anchored, provided for, or can be obtained through the PCB. The PCB is generated during process initialization and deleted during process termination.

The following tables show the format of the PCB.

Table 1 shows the PCB fields and Table 4 describes their contents.
Table 2 shows the PCB constants.
Table 3 shows the PCB cross-reference information.

Table 1. Process control block (PCB) field descriptions
Offsets		Type	Len	Name ( * = Reserved)	Description
Dec	Hex	Type	Len	Name ( * = Reserved)	Description
0	(0)	STRUCTURE	76	CEEPCB	PCB mapping
0	(0)	CHARACTER	76	CEEPCB_EXTERNAL	External portion
0	(0)	CHARACTER	8	CEEPCBEYE	Eye catcher 'CEEPCB '
8	(8)	BITSTRING	1	CEEPCBSYSTM	Underlying Operating System
9	(9)	BITSTRING	1	CEEPCBHRDWR	Underlying Hardware
10	(A)	BITSTRING	1	CEEPCBSBSYS	Underlying Subsystem
11	(B)	BITSTRING	1	CEEPCBFLAG2
		`1... ....`		CEEPCBBIMODAL	Bimodal addressing is avail.
		`.1.. ....`		CEEPCB_LVFORM	LIBVEC format 1=stat./0=dynam
		`..1. ....`		CEEPCB_VECTOR	Vector hardware available
		`...1 ....`		CEEPCB_CL24	CEL Libvec AMODE24 is built
		`.... 1...`		CEEPCB_OMVS	z/OS UNIX is up and available
		`.... .1..`		*	RESERVED
		`.... ..1.`		CEEPCB_PICI	PICI environment
		`.... ...1`		CEEPCB_REUSE	This CCIS process contains a reusable enclave environment
12	(C)	ADDRESS	4	CEEPCBDBGEH	A(debug event handler)
16	(10)	CHARACTER	8	CEEPCBDBGRSVD	Reserved for debugger
24	(18)	ADDRESS	4	CEEPCBDMEMBR	A(process member list)
28	(1C)	ADDRESS	4	CEEPCB_ZLOD	A(process load routine)
32	(20)	ADDRESS	4	CEEPCB_ZDEL	A(process delete routine)
36	(24)	ADDRESS	4	CEEPCB_ZGETST	A(process get storage rtn)
40	(28)	ADDRESS	4	CEEPCB_ZFREEST	A(process free storage rtn)
44	(2C)	ADDRESS	4	CEEPCB_LVTL	Address of a Lang Env library table that contains info about Language Environment libvecs, to determine which transfer vector should be used to access a library routine and be signal safed.
48	(30)	ADDRESS	4	CEEPCBRCB	Address of the RCB
52	(34)	ADDRESS	4	CEEPCB_SYSEIB	A(CICS® System EIB)
The following three fields are used by the CEEXGPPS (get permanent process storage) macro. This macro allows the member languages to quickly allocate storage at the process level that is freed only by CEL after member process termination.
56	(38)	SIGNED	4	CEEPCBPSL	Length of perm process stg
60	(3C)	ADDRESS	4	CEEPCBPSA	Addr of perm process stg
64	(40)	ADDRESS	4	CEEPCBPSRA	Perm process stg overflow routine address
68	(44)	BITSTRING	4	CEEPCB_OMVS_LEVEL	z/OS UNIX release level (Multiple bits may be set)
		`1... ....`		*	Reserved
		`.1.. ....`		CEEPCB_OMVS_1120	HOM1120 functions are present.
		`..1. ....`		CEEPCB_OMVS_1130	HOM1130 functions are present.
68	(44)	BITSTRING	3	*	Reserved
72	(48)	ADDRESS	4	CEEPCB_CHAIN	Pointer to next PCB on PICI environment chain
76	(4C)	ADDRESS	4	CEEPCB_VSSFE	Address of the stack segment free routine
80	(50)	ADDRESS	4	CEEPCBPRFEH	Address of profile event handler
84	(54)	BITSTRING	1	CEEPCBFLAG6	Additional PCB flags
		`1... ....`	4	CEEPCB_ESAME	ESAME-supported
		`.111 ....`		*	Reserved
		`.... 1...`		CEEPCB_SIMD	SIMD-supported
85	(55)	CHARACTER	3	CEEPCB_RSRVED	Reserved
88	(58)	ADDRESS	4	*	Reserved
92	(5C)	ADDRESS	4	CEEPCB_DBGINFO	Address of debugger Info block

Table 2. Process control block (PCB) constants
Len	Type	Value	Name	Description
Constants
4	DECIMAL	16384	CEEPCB_IS_SIZE	Init dummy stk size
4	DECIMAL	2048	CEEPCB_LIS_SIZE	Init dummy lib size
CAUTION: CEEPCB_IS_SIZE and CEEPCB_LIS_SIZE must be multiple of doubleword size.
4	DECIMAL	8	CEEPCB_MAXLVTNUM	Maximum library transfer vector tables in Language Environment
Declare constants for operating system, hardware, and subsystem CEEPCBSYSTM, CEEPCBHRDWR, CEEPCBSYS
1	DECIMAL	0	CEEPCBSYUND	Undefined
1	DECIMAL	1	CEEPCBSYUNS	Unsupported
1	DECIMAL	2	CEEPCBSYVM	VM
1	DECIMAL	3	CEEPCBSYMVS	z/OS Underlying hardware
1	DECIMAL	0	CEEPCBHWUND	Undefined
1	DECIMAL	1	CEEPCBHWUNS	Unsupported
1	DECIMAL	2	CEEPCBHW370	System/370 non-X
1	DECIMAL	3	CEEPCBHWXA	System/370 XA
1	DECIMAL	4	CEEPCBHWESA	System/370 ESA underlying subsystem
1	DECIMAL	0	CEEPCBSSUND	Undefined
1	DECIMAL	1	CEEPCBSSUNS	Unsupported
1	DECIMAL	2	CEEPCBSSNON	No subsystem
1	DECIMAL	3	CEEPCBSSTSO	TSO
1	DECIMAL	5	CEEPCBSSCIC	CICS
Declare constants describing state of process
1	DECIMAL	0	CEEPCBSTATE_INIT	Process init
1	DECIMAL	1	CEEPCBSTATE_TERM	Process term
1	DECIMAL	2	CEEPCBSTATE_ACTIVE	Process active

Table 3. Process control block (PCB) cross-reference
Name	Hex Offset	Hex Value	Level
CEEPCB	0		1
CEEPCB_CHAIN	48		3
CEEPCB_CL24	B	10	4
CEEPCB_DBGINFO	5C		3
CEEPCB_ESAME	54	80	4
CEEPCB_EXTERNAL	0		2
CEEPCB_LVFORM	B	40	4
CEEPCB_LVTL	2C		3
CEEPCB_OMVS	B	08	4
CEEPCB_OMVS_LEVEL	44		3
CEEPCB_OMVS_1120	44	40	4
CEEPCB_OMVS_1130	44	20	4
CEEPCB_PICI	B	02	4
CEEPCB_REUSE	B	01	4
CEEPCB_SYSEIB	34		3
CEEPCB_SIMD	54	08	4
CEEPCB_VECTOR	B	20	4
CEEPCB_VSSFE	4C		3
CEEPCB_ZDEL	20		3
CEEPCB_ZFREEST	28		3
CEEPCB_ZGETST	24		3
CEEPCB_ZLOD	1C		3
CEEPCBBIMODAL	B	80	4
CEEPCBDBGEH	C		3
CEEPCBDBGRSVD	10		3
CEEPCBDMEMBR	18		3
CEEPCBEYE	0		3
CEEPCBFLAG2	B		3
CEEPCBFLAG6	54		3
CEEPCBHRDWR	9		3
CEEPCBPRFEH	50		3
CEEPCBPSA	3C		3
CEEPCBPSL	38		3
CEEPCBPSRA	40		3
CEEPCBRCB	30		3
CEEPCBSBSYS	A		3
CEEPCBSYSTM	8		3
RESERVED	B	04	4

Table 4 describes the PCB fields in more detail.

Table 4. PCB field descriptions
Field	Contents
CEEPCBEYE	8-character eyecatcher 'CEEPCB'.
CEEPCBSYSTM	Underlying operating system. The value indicates the operating system supporting the active program. The values are defined as follows: 0 Undefined. This value should never occur after initializing Language Environment 1 Unsupported 2 VM/ESA 3 z/OS®
CEEPCBHRDWR	Underlying hardware The value indicates the type of hardware on which the program is executing; the values are defined as follows: 0 Undefined. This value should never occur after initializing Language Environment 1 Unsupported 2 System/370, non-XA 3 System/370, XA 4 System/370, ESA
CEEPCBSBSYS	Underlying subsystem The value indicates the subsystem, if any, on which the program is executing; the values are defined as follows: 0 Undefined. This value should never occur after initializing Language Environment 1 Unsupported 2 None. The program is not executing under a subsystem according to Language Environment 3 TSO 4 Reserved 5 CICS 6 - 7 Reserved
CEEPCBFLAG2	PCB flag bits; the bits are defined as follows: 0 CEEPCBBIMODAL. When 1, this indicates the hardware is capable of bimodal addressing 1 CEEPCB_LVFORM. . Reserved 2 CEEPCB_VECTOR – When 1, the vector facility is available on the hardware 3 CEEPCB_CL24. LIBVEC for AMODE24 is available 4 CEEPCB_OMVS. z/OS UNIX is up and available 5 Reserved 6 CEEPCB_PICI. The PICI environment is in effect 7 CEEPCB_REUSE. When 1, the CICS process contains a reusable enclave environment. This flag is required to indicate how Language Environment will getmain, freemain, load, or delete resources upon requests in a reusable enclave environment. These resources must be freed explicitly during transaction termination.
CEEPCBDBGEH	Address of the debug tool event handler. This field holds the address of the debug tool event handler. When this field is zero, a debug tool has not been initialized.
CEEPCBDBGRSVD	Reserved for the debug tool's use. A doubleword that is reserved for the debug tool's use. It is zeroed by Language Environment process initialization.
CEEPCBMEMBR	Address of the process level member list. An entry is reserved for each member known to Language Environment. There is one member list per process. The process level member list has the same format as the enclave level member list. For details, see Language Environment member list and event handler.
CEEPCB_ZLOD	Process-level LOAD service. This is the address of a LOAD service. Routines loaded using this service persist across enclaves within this process. For details, see Loading and deleting programs in different environments.
CEEPCB_ZDEL	Process level DELETE service. This is the address of a DELETE service. Routines loaded using CEEPCB_ZLOD must be deleted using this service. For details, see Loading and deleting programs in different environments.
CEEPCB_ZGETST	Process level GETMAIN service. This is the address of a GETMAIN service. Storage obtained using this service persist across enclaves within this process.
CEEPCB_ZFREEST	Process level FREEMAIN service. This is the address of a FREEMAIN service. Storage obtained using CEEPCB_ZGETST must be freed using this service.
CEEPCB_LVTL	Address of a Language Environment library vector.
CEEPCBRCB	Address of the RCB.
CEEPCB_SYSEIB	Address of CICS system EIB.
CEEPCBPSL	Length of permanent process storage. This field is used by the CEEXGPPS (get permanent process storage) macro. This macro allows the member languages to quickly allocate storage at the process level that is freed only by Language Environment after member process termination.
CEEPCBPSA	Address of permanent process storage. This field is used by the CEEXGPPS (get permanent process storage) macro. This macro allows the member languages to quickly allocate storage at the process level that is freed only by Language Environment after member process termination.
CEEPCBPSRA	Permanent process storage overflow routine address table that contains information for all Language Environment LIBVECs that allow signal safing of Language Environment library for asynchronous signals. This field is used by the CEEXGPPS (get permanent process storage) macro. This macro allows the member languages to quickly allocate storage at the process level that is freed only by Language Environment after member process termination.
CEEPCB_OMVS_LEVEL	z/OS UNIX release level. The flags are as follows: 0 Reserved 1 HOM1120 functions are present 2 HOM1130 functions are present
CEEPCB_CHAIN	Used to run the PICI environment chain; it will be NULL when there is no next environment in the chain.
CEEPCB_VSSFE	Address of the stack segment free routine.
CEEPCBPRFEH	Address of the profile event handler
CEEPCBFLAG6	Additional PCB flag bits. The bits are defined as follows: 0 CEEPCB_ESAME 1 Level 1 tracing on 2 Level 2 tracing on 3 Debugger was HFS loaded 4 SIMD-supported 5-7 Reserved
CEEPCB_DBGINFO	Address of the debugger info block.