OpenVMS RTL Library (LIB$) Manual

Document revision date: 19 July 1999

OpenVMS RTL Library (LIB$) Manual

Contents

Index

LIB$SPAWN

The Spawn Subprocess routine requests the command language interpreter (CLI) of the calling process to spawn a subprocess for executing CLI commands. LIB$SPAWN provides the same function as the DCL command SPAWN.

Format

LIB$SPAWN [command-string] [,input-file] [,output-file] [,flags] [,process-name] [,process-id] [,completion-status-address] [,byte-integer-event-flag-num] [,AST-address] [,varying-AST-argument] [,prompt-string] [,cli] [,table]

RETURNS

OpenVMS usage: cond_value

type: longword (unsigned)

access: write only

mechanism: by value

Arguments

command-string

OpenVMS usage: char_string

type: character string

access: read only

mechanism: by descriptor

CLI command to be executed by the spawned subprocess. The command-string argument is the address of a descriptor pointing to this CLI command string. If command-string is omitted, commands are taken from the file specified by input-file.
input-file

OpenVMS usage: char_string

type: character string

access: read only

mechanism: by descriptor

Equivalence name to be associated with the logical name SYS$INPUT in the logical name table for the subprocess. The input-file argument is the address of a descriptor pointing to this equivalence string. If input-file is omitted, the default is the caller's SYS$INPUT.
output-file

OpenVMS usage: char_string

type: character string

access: read only

mechanism: by descriptor

Equivalence name to be associated with the logical names SYS$OUTPUT and SYS$ERROR in the logical name table for the subprocess. The output-file argument is the address of a descriptor pointing to this equivalence string. If output-file is omitted, the default is the caller's SYS$OUTPUT.
flags

OpenVMS usage: mask_longword

type: longword (unsigned)

access: read only

mechanism: by reference

Flag bits that designate optional behavior. The flags argument is the address of an unsigned longword that contains these flag bits. By default, all flags are clear.
These flags are defined as follows:

Bit Symbol Meaning

0 NOWAIT If this bit is set, the calling process continues executing in parallel with the subprocess. If this bit is clear, the calling process hibernates until the subprocess completes.

1 NOCLISYM If this bit is set, the spawned subprocess does not inherit CLI symbols from its caller. If this bit is clear, the subprocess inherits all currently defined CLI symbols. You may want to specify NOCLISYM to help prevent commands redefined by symbol assignments from affecting the spawned commands.

2 NOLOGNAM If this bit is set, the spawned subprocess does not inherit process logical names from its caller. If this bit is clear, the subprocess inherits all currently defined process logical names. You may want to specify NOLOGNAM to help prevent commands redefined by logical name assignments from affecting the spawned commands.

3 NOKEYPAD If this bit is set, the keypad symbols and state are not passed to the subprocess. If this bit is not set, the keypad settings are passed to the subprocess.

4 NOTIFY If this bit is set, a message is broadcast to SYS$OUTPUT when the subprocess completes or aborts. If this bit is not set, no message is broadcast. This bit should not be set unless the NOWAIT bit is also set.

5 NOCONTROL If this bit is set, no carriage-return/line-feed is prefixed to any prompt string. If this bit is not set, a carriage-return/line-feed is prefixed to any prompt string specified.

6 TRUSTED If this bit is set, it indicates a SPAWN command on behalf of the application. If this bit is not set, it indicates that the SPAWN command originates from user. SPAWN commands originating from users are disallowed in captive accounts (DCL).

7 AUTHPRIV If this bit is set, the subprocess inherits the caller's authorized privileges. If this bit is clear, the spawned processes' authorized mask is set equal to the caller's current (active) privilege mask.

8 SUBSYSTEM If this bit is set, a spawned process inherits protected subsystem IDs for the duration of LOGINOUT.EXE (used to map the CLI). The IDs will be removed in the process of transferring control to the CLI (as a user mode $RUNDWN is performed). If this bit is clear, LOGINOUT does not execute under the subsystem IDs.

Bits 9 through 31 are reserved for future expansion and must be zero. Symbolic flag names are defined in libraries supplied by Compaq in module $CLIDEF. They are CLI$M_NOWAIT, CLI$M_NOCLISYM, CLI$M_NOLOGNAM, CLI$M_NOKEYPAD, CLI$M_NOTIFY, CLI$M_NOCONTROL, CLI$M_TRUSTED, CLI$M_AUTHPRIV, and CLI$M_SUBSYSTEM.
process-name

OpenVMS usage: process_name

type: character string

access: read only

mechanism: by descriptor

Name defined for the subprocess. The process-name argument is the address of a descriptor pointing to this name string. If process-name is omitted, a unique process name will be generated. If you supply a name and it is not unique, LIB$SPAWN will return the condition value SS$_DUPLNAM.
process-id

OpenVMS usage: process_id

type: longword (unsigned)

access: write only

mechanism: by reference

Process identification of the spawned subprocess. The process-id argument is the address of an unsigned longword that contains this process identification value.
This process identification value is meaningful only if the NOWAIT flags bit is set.
completion-status-address

OpenVMS usage: address

type: address

access: read only

mechanism: by value

The final completion status of the subprocess. The completion-status-address argument contains the address of the status. The system writes the value of the final completion status of the subprocess into completion-status-address when the subprocess completes. If the subprocess returns a status code of 0, the system writes SS$_NORMAL into this address.
If the NOWAIT flags bit is set, the completion-status-address is updated asynchronously when the subprocess completes. Use the byte-integer-event-flag-num or AST-address arguments to determine when the subprocess has completed. Your program must ensure that the address is still valid when the value is written.
byte-integer-event-flag-num

OpenVMS usage: byte_unsigned

type: byte (unsigned)

access: read only

mechanism: by reference

The number of a local event flag to be set when the spawned subprocess completes. The byte-integer-event-flag-num argument is the address of an unsigned byte that contains this event flag number. If byte-integer-event-flag-num is omitted, no event flag is set.
Specifying byte-integer-event-flag-num is meaningful only if the NOWAIT flags bit is set.
AST-address

OpenVMS usage: procedure

type: procedure value

access: call without stack unwinding

mechanism: by value

Routine to be called by means of an AST when the subprocess completes.
Specifying AST-address is meaningful only if the NOWAIT flags bit is set.
varying-AST-argument

OpenVMS usage: user_arg

type: longword (unsigned)

access: read only

mechanism: by value

A value to be passed to the AST routine. Typically, the varying-AST-argument argument is the address of a block of storage the AST routine will use.
Specifying varying-AST-argument is meaningful only if the NOWAIT flags bit is set and if AST-address has been specified.
prompt-string

OpenVMS usage: char_string

type: character string

access: read only

mechanism: by descriptor

Prompt string to use in the subprocess. The prompt-string argument is the address of a descriptor pointing to this prompt string. If prompt-string is omitted, the subprocess uses the same prompt string that the parent process uses.
cli

OpenVMS usage: char_string

type: character string

access: read only

mechanism: by descriptor

File specification for the command language interpreter (CLI) to be run in the subprocess. The cli argument is the address of this file specification string's descriptor. The CLI specified must reside in SYS$SYSTEM with a file type of .EXE, and it must be installed. No directory or file type may be specified. The cli argument must be specified in uppercase characters.
If cli is omitted, the subprocess uses the same CLI as the parent process. If cli is specified, no context is copied to the subprocess.
table

OpenVMS usage: char_string

type: character string

access: read only

mechanism: by descriptor

File specification for the command tables to be used by the spawned process. The table argument is the address of this file specification string's descriptor. The table specified must reside in SYS$SHARE with a file type of .EXE, and it must be installed.
If table is omitted, the subprocess uses the same table as the parent process.

Bit	Symbol	Meaning
0	NOWAIT	If this bit is set, the calling process continues executing in parallel with the subprocess. If this bit is clear, the calling process hibernates until the subprocess completes.
1	NOCLISYM	If this bit is set, the spawned subprocess does not inherit CLI symbols from its caller. If this bit is clear, the subprocess inherits all currently defined CLI symbols. You may want to specify NOCLISYM to help prevent commands redefined by symbol assignments from affecting the spawned commands.
2	NOLOGNAM	If this bit is set, the spawned subprocess does not inherit process logical names from its caller. If this bit is clear, the subprocess inherits all currently defined process logical names. You may want to specify NOLOGNAM to help prevent commands redefined by logical name assignments from affecting the spawned commands.
3	NOKEYPAD	If this bit is set, the keypad symbols and state are not passed to the subprocess. If this bit is not set, the keypad settings are passed to the subprocess.
4	NOTIFY	If this bit is set, a message is broadcast to SYS$OUTPUT when the subprocess completes or aborts. If this bit is not set, no message is broadcast. This bit should not be set unless the NOWAIT bit is also set.
5	NOCONTROL	If this bit is set, no carriage-return/line-feed is prefixed to any prompt string. If this bit is not set, a carriage-return/line-feed is prefixed to any prompt string specified.
6	TRUSTED	If this bit is set, it indicates a SPAWN command on behalf of the application. If this bit is not set, it indicates that the SPAWN command originates from user. SPAWN commands originating from users are disallowed in captive accounts (DCL).
7	AUTHPRIV	If this bit is set, the subprocess inherits the caller's authorized privileges. If this bit is clear, the spawned processes' authorized mask is set equal to the caller's current (active) privilege mask.
8	SUBSYSTEM	If this bit is set, a spawned process inherits protected subsystem IDs for the duration of LOGINOUT.EXE (used to map the CLI). The IDs will be removed in the process of transferring control to the CLI (as a user mode $RUNDWN is performed). If this bit is clear, LOGINOUT does not execute under the subsystem IDs.

Description

The subprocess created by LIB$SPAWN inherits the following attributes from the caller's environment:

Process logical names
Global and local CLI symbols
Default device and directory
Process privileges
Process nondeductible quotas
Current command verification setting

The subprocess does not inherit process-permanent files nor routine or image context.
Though the subprocess inherits the caller's process privileges as its own process privileges, the set of authorized privileges in the subprocess is inherited from the caller's current privileges. If the calling image is installed with elevated privileges, these privileges are not available to the the subprocess until a SET PROCESS/PRIVILEGE command or equivalent $SETPRV call is performed in the subprocess to enable these privileges.
If the calling image is installed with elevated privileges, it should disable those privileges around the call to LIB$SPAWN unless the environment of the subprocess is strictly controlled. Otherwise, there is a possibility of a security breach due to elevated privileges accidentally being made available to the user.
If neither command-string nor input-file is present, command input is taken from the parent terminal. If both command-string and input-file are present, the subprocess first executes command-string and then reads from input-file. If only command-string is specified, the command is executed, and the subprocess is terminated. If input-file is specified, the subprocess is terminated by either a LOGOUT command or an end-of-file.
The subprocess does not inherit process-permanent files nor routine or image context. No LOGIN.COM file is executed.
Unless the NOWAIT flags bit is set, the caller's process is put into hibernation until the subprocess finishes. Because the caller's process hibernates in supervisor mode, any user-mode ASTs queued for delivery to the caller are not delivered until the caller reawakes. Control can also be restored to the caller by means of an ATTACH command or by a suitable call to LIB$ATTACH from the subprocess.
This routine is supported for use only with the DCL command language interpreter. If used when the current CLI is MCR, the error status LIB$_NOCLI is returned.
If an image is run directly as a subprocess or as a detached process, there is no CLI present to perform this function. In such cases, the error status LIB$_NOCLI is returned.
Programs depending on embedded DCL commands may not function properly when run under other command language interpreters that may be supported by future versions of OpenVMS operating systems.
See the OpenVMS DCL Dictionary for a complete description of the SPAWN command.

Condition Values Returned

SS$_NORMAL Routine successfully completed.

SS$_ACCVIO Access violation. One of the string arguments to LIB$SPAWN could not be read, or completion-status-address could not be written.

SS$_DUPLNAM Duplicate process name. If the argument process-name was specified, it duplicated an existing process name. If process-name was omitted, LIB$SPAWN was unable to create a unique name for the subprocess.

fac$_xxx Other error trying to create subprocess.

LIB$_INVARG Invalid argument. The optional argument flags was specified, and a bit other than bits 0 through 8 was set.

LIB$_INVSTRDES Invalid string descriptor. One of the string arguments had an invalid descriptor.

LIB$_NOCLI No CLI present to perform function. The calling process did not have a CLI to perform the function, or the CLI did not support the request type. Note that an image run as a subprocess or detached process does not have a CLI.

If an error is encountered during subprocess creation, the status value for that error is returned by LIB$SPAWN.

Example


ISTAT=LIB$SPAWN(,,,CLI$M_NOKEYPAD,,,,,,,'> ') IF (.NOT. ISTAT) CALL LIB$STOP(%VAL(ISTAT))

This Fortran fragment shows a call to LIB$SPAWN from within a Fortran program. A subprocess is spawned taking input from SYS$INPUT and giving output to SYS$OUTPUT. The keypad state is not passed to the subprocess. A prompt string of "> " is specified for the subprocess.

LIB$STAT_TIMER

The Statistics, Return Accumulated Times and Counts routine returns to its caller one of five available statistics accumulated since the last call to LIB$INIT_TIMER. Unlike LIB$SHOW_TIMER, which formats the values for output, LIB$STAT_TIMER returns the value as an unsigned longword or quadword.

Format

LIB$STAT_TIMER code ,value-argument [,handle-address]

RETURNS

OpenVMS usage: cond_value

type: longword (unsigned)

access: write only

mechanism: by value

Arguments

code

OpenVMS usage: longword_signed

type: longword integer (signed)

access: read only

mechanism: by reference

The address of a signed longword integer that contains a code to specify the statistic to be returned. The code specification must be an integer from 1 to 5.
The following values are allowed for code:

Value Statistic Returned

1 Elapsed real time (quadword, in system time format)

2 Elapsed CPU time (longword, in 10 millisecond increments)

3 Count of buffered I/O operations (longword)

4 Count of direct I/O operations (longword)

5 Count of page faults (longword)

value-argument

OpenVMS usage: user_arg

type: unspecified

access: write only

mechanism: by reference

The statistic returned by LIB$STAT_TIMER. The value-argument argument contains the address of a longword or quadword that is this statistic. All statistics are longword integers except elapsed real time, which is a quadword.
See the OpenVMS System Services Reference Manual for more details on the system time format.
handle-address

OpenVMS usage: address

type: longword (unsigned)

access: read only

mechanism: by reference

Pointer to a block of storage. The optional handle-address argument contains the address of an unsigned longword that is this pointer.
If handle-address is specified, LIB$STAT_TIMER assumes that LIB$INIT_TIMER has been called with the same value of handle-address. Handle-address is an optional argument. If it is not specified, LIB$STAT_TIMER uses internal storage.

Value	Statistic Returned
1	Elapsed real time (quadword, in system time format)
2	Elapsed CPU time (longword, in 10 millisecond increments)
3	Count of buffered I/O operations (longword)
4	Count of direct I/O operations (longword)
5	Count of page faults (longword)

Description

Only one of the five statistics is returned by each call to LIB$STAT_TIMER. The elapsed time is returned in the system quadword format. Therefore the receiving area should be eight bytes long. All other returned values are longwords.
LIB$SHOW_TIMER and LIB$STAT_TIMER are relatively simple tools for testing the performance of a new application. Note that LIB$INIT_TIMER must be called prior to any calls to LIB$SHOW_TIMER or LIB$STAT_TIMER.
To obtain more detailed information, use LIB$GETJPI (Get Job/Process Information) or the system service $GETTIM.
The following summary shows the differences between LIB$SHOW_TIMER and LIB$STAT_TIMER:

Code Statistic Format for
LIB$SHOW_TIMER Format for
LIB$STAT_TIMER

1 Elapsed real time hhhh: mm: ss. cc Quadword in system time format

2 Elapsed CPU time hhhh: mm: ss. cc Longword in 10-millisecond increments

3 Count of buffered I/O operations nnnn Longword

4 Count of direct I/O operations nnnn Longword

5 Count of page faults nnnn Longword

When you call LIB$INIT_TIMER, you must use the optional handle-address argument only if you want to keep several sets of statistics simultaneously. This argument points to a block in heap storage where the statistics are to be stored.
You need to call LIB$FREE_TIMER only if you have specified handle-address in LIB$INIT_TIMER and you want to deallocate all heap storage resources. In most cases, the implicit deallocation at program exit time will be sufficient.

Code	Statistic	Format for LIB$SHOW_TIMER	Format for LIB$STAT_TIMER
1	Elapsed real time	hhhh: mm: ss. cc	Quadword in system time format
2	Elapsed CPU time	hhhh: mm: ss. cc	Longword in 10-millisecond increments
3	Count of buffered I/O operations	nnnn	Longword
4	Count of direct I/O operations	nnnn	Longword
5	Count of page faults	nnnn	Longword

Condition Values Returned

SS$_NORMAL Routine successfully completed.

LIB$_INVARG Invalid argument. Either code or handle-address is invalid.

Example


PROGRAM STAT_TIMER(INPUT,OUTPUT); {+} { This Pascal example program demonstrates the use of { LIB$STAT_TIMER. {-} TYPE BYTE = [BYTE] 0..255; WORD = [WORD] 0..65535; QUADWORD_SYSTEM_TIME = [QUAD] RECORD FIRST_LONGWORD : UNSIGNED; SECOND_LONGWORD : UNSIGNED; END; VAR ELAPSED_REAL_TIME : QUADWORD_SYSTEM_TIME; ELAPSED_STRING : VARYING [32] OF CHAR; PAGE_FAULT_COUNT : UNSIGNED; RETURNED_STATUS : UNSIGNED; [EXTERNAL] FUNCTION LIB$INIT_TIMER( HANDLE_ADR : [REFERENCE] UNSIGNED := %IMMED 0 ) : INTEGER; EXTERNAL; [EXTERNAL] FUNCTION LIB$STAT_TIMER( CODE : INTEGER; VALUE : [UNSAFE,REFERENCE] PACKED ARRAY [L..U:INTEGER] OF BYTE; HANDLE_ADR : [REFERENCE] UNSIGNED := %IMMED 0 ) : INTEGER; EXTERNAL; [EXTERNAL] FUNCTION LIB$STOP( CONDITION_STATUS : [IMMEDIATE,UNSAFE] UNSIGNED; FAO_ARGS : [IMMEDIATE,UNSAFE,LIST] UNSIGNED ) : INTEGER; EXTERNAL; [EXTERNAL] FUNCTION LIB$SYS_ASCTIM( OUT_LEN : [REFERENCE] WORD := %IMMED 0; VAR DST_STR : PACKED ARRAY [L..U:INTEGER] OF CHAR; USER_TIME : QUADWORD_SYSTEM_TIME := %IMMED 0; CNV_FLG : UNSIGNED := %IMMED 0 ) : INTEGER; EXTERNAL; BEGIN {+} { Call LIB$INIT_TIMER to initialize RTL internal counters. {-} RETURNED_STATUS := LIB$INIT_TIMER; IF NOT ODD(RETURNED_STATUS) THEN LIB$STOP(RETURNED_STATUS); {+} { Print a line of text to waste time. {-} WRITELN('Spend time to acquire elapsed real time and page faults'); {+} { Call LIB$STAT_TIMER to retrieve statistics values. {-} RETURNED_STATUS := LIB$STAT_TIMER(1,ELAPSED_REAL_TIME); IF NOT ODD(RETURNED_STATUS) THEN LIB$STOP(RETURNED_STATUS); RETURNED_STATUS := LIB$STAT_TIMER(5,PAGE_FAULT_COUNT); IF NOT ODD(RETURNED_STATUS) THEN LIB$STOP(RETURNED_STATUS); {+} { Print the statistics retrieved from LIB$STAT_TIMER. {-} WRITELN('Page fault count is ',PAGE_FAULT_COUNT:1); RETURNED_STATUS := LIB$SYS_ASCTIM( ELAPSED_STRING.LENGTH, ELAPSED_STRING.BODY, ELAPSED_REAL_TIME, 1); IF NOT ODD(RETURNED_STATUS) THEN LIB$STOP(RETURNED_STATUS); WRITELN('Elapsed real time is ',ELAPSED_STRING); END.

PROGRAM STAT_TIMER(INPUT,OUTPUT); 
 
{+} 
{ This Pascal example program demonstrates the use of 
{ LIB$STAT_TIMER. 
{-} 
 
    TYPE 
          BYTE = [BYTE] 0..255; 
          WORD = [WORD] 0..65535; 
          QUADWORD_SYSTEM_TIME = [QUAD] RECORD 
              FIRST_LONGWORD  : UNSIGNED; 
              SECOND_LONGWORD : UNSIGNED; 
          END; 
 
    VAR 
          ELAPSED_REAL_TIME : QUADWORD_SYSTEM_TIME; 
          ELAPSED_STRING    : VARYING [32] OF CHAR; 
          PAGE_FAULT_COUNT  : UNSIGNED; 
          RETURNED_STATUS   : UNSIGNED; 
 
    [EXTERNAL] FUNCTION LIB$INIT_TIMER( 
          HANDLE_ADR : [REFERENCE] UNSIGNED := %IMMED 0 
          ) : INTEGER; EXTERNAL; 
 
    [EXTERNAL] FUNCTION LIB$STAT_TIMER( 
          CODE       : INTEGER; 
          VALUE      : [UNSAFE,REFERENCE] PACKED ARRAY [L..U:INTEGER] OF BYTE; 
          HANDLE_ADR : [REFERENCE] UNSIGNED := %IMMED 0 
          ) : INTEGER; EXTERNAL; 
 
    [EXTERNAL] FUNCTION LIB$STOP( 
          CONDITION_STATUS : [IMMEDIATE,UNSAFE] UNSIGNED; 
          FAO_ARGS         : [IMMEDIATE,UNSAFE,LIST] UNSIGNED 
          ) : INTEGER; EXTERNAL; 
 
    [EXTERNAL] FUNCTION LIB$SYS_ASCTIM( 
          OUT_LEN     : [REFERENCE] WORD := %IMMED 0; 
          VAR DST_STR : PACKED ARRAY [L..U:INTEGER] OF CHAR; 
          USER_TIME   : QUADWORD_SYSTEM_TIME := %IMMED 0; 
          CNV_FLG     : UNSIGNED := %IMMED 0 
          ) : INTEGER; EXTERNAL; 
 
BEGIN 
 
{+} 
{ Call LIB$INIT_TIMER to initialize RTL internal counters. 
{-} 
 
RETURNED_STATUS := LIB$INIT_TIMER; 
IF NOT ODD(RETURNED_STATUS) 
THEN 
    LIB$STOP(RETURNED_STATUS); 
 
{+} 
{ Print a line of text to waste time. 
{-} 
 
WRITELN('Spend time to acquire elapsed real time and page faults'); 
 
{+} 
{ Call LIB$STAT_TIMER to retrieve statistics values. 
{-} 
 
RETURNED_STATUS := LIB$STAT_TIMER(1,ELAPSED_REAL_TIME); 
IF NOT ODD(RETURNED_STATUS) 
THEN 
    LIB$STOP(RETURNED_STATUS); 
 
RETURNED_STATUS := LIB$STAT_TIMER(5,PAGE_FAULT_COUNT); 
IF NOT ODD(RETURNED_STATUS) 
THEN 
    LIB$STOP(RETURNED_STATUS); 
 
{+} 
{ Print the statistics retrieved from LIB$STAT_TIMER. 
{-} 
 
WRITELN('Page fault count is ',PAGE_FAULT_COUNT:1); 
 
RETURNED_STATUS := LIB$SYS_ASCTIM( 
                      ELAPSED_STRING.LENGTH, 
                      ELAPSED_STRING.BODY, 
                      ELAPSED_REAL_TIME, 
                      1); 
IF NOT ODD(RETURNED_STATUS) 
THEN 
    LIB$STOP(RETURNED_STATUS); 
 
WRITELN('Elapsed real time is ',ELAPSED_STRING); 
 
END.

This Pascal program demonstrates the use of LIB$STAT_TIMER. The output generated by this program is as follows:
Spend time to acquire elapsed real time and page faults Page fault count is 22 Elapsed real time is 00:00:00.61

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OpenVMS usage:	cond_value
type:	longword (unsigned)
access:	write only
mechanism:	by value

OpenVMS usage:	char_string
type:	character string
access:	read only
mechanism:	by descriptor

OpenVMS usage:	mask_longword
type:	longword (unsigned)
access:	read only
mechanism:	by reference

OpenVMS usage:	process_name
type:	character string
access:	read only
mechanism:	by descriptor

OpenVMS usage:	process_id
type:	longword (unsigned)
access:	write only
mechanism:	by reference

OpenVMS usage:	address
type:	address
access:	read only
mechanism:	by value

OpenVMS usage:	byte_unsigned
type:	byte (unsigned)
access:	read only
mechanism:	by reference

OpenVMS usage:	procedure
type:	procedure value
access:	call without stack unwinding
mechanism:	by value

OpenVMS usage:	user_arg
type:	longword (unsigned)
access:	read only
mechanism:	by value

SS$_NORMAL	Routine successfully completed.
SS$_ACCVIO	Access violation. One of the string arguments to LIB$SPAWN could not be read, or completion-status-address could not be written.
SS$_DUPLNAM	Duplicate process name. If the argument process-name was specified, it duplicated an existing process name. If process-name was omitted, LIB$SPAWN was unable to create a unique name for the subprocess.
fac$_xxx	Other error trying to create subprocess.
LIB$_INVARG	Invalid argument. The optional argument flags was specified, and a bit other than bits 0 through 8 was set.
LIB$_INVSTRDES	Invalid string descriptor. One of the string arguments had an invalid descriptor.
LIB$_NOCLI	No CLI present to perform function. The calling process did not have a CLI to perform the function, or the CLI did not support the request type. Note that an image run as a subprocess or detached process does not have a CLI.

OpenVMS usage:	longword_signed
type:	longword integer (signed)
access:	read only
mechanism:	by reference