Linkage editor control statements are shown using a mode

Read this topic which clear your questions.

The linkage editor (PGM=IEWL) is used to create an executable load
module from an object deck. The linkage editor must be used to make
an executable copy of a compiled or assembled program. External
symbols in the object module(s), optional linkage editor control
statements, and linkage editor JCL parameters determine how the
finished load module is to be constructed.

NOTE: If your installation has DFSMS/MVS installed, the linkage
editor at your site is called the "binder" and is part of the MVS
Program Management Services component. The terms "binder" and
"linkage editor" can be used interchangeably when reading the
information below. The binder supports all of the functions of
the linkage editor, and also supports linking of "program objects"
and PDSE data sets. Program objects reside in PDSE data sets and
are page-mapped in virtual storage; many of the restrictions that
applied to the size of load modules do not apply to program
objects.

Sample JCL for the linkage editor appears below; following the JCL is
a discussion of each DD statement required by the linkage editor and
what each is used for. An explanation of linkage editor control
statements follows the JCL discussion, and linkage editor usage
examples appear at the end of this reference item.

Sample linkage editor JCL:

//JS10 EXEC PGM=IEWL,REGION=1024K,
// PARM='parms. ' Parameters (optional)
//SYSPRINT DD SYSOUT=* Output Messages
//SYSTERM DD SYSOUT=* Output Messages (optional)
//SYSLIN DD DSN=. DISP=SHR Input Object Module File
// DD DDNAME=SYSIN (Points to optional input)
//SYSLMOD DD DSN=. DISP=SHR Output Load Module File
//SYSLIB DD DSN=. DISP=SHR Optional 'Auto-call' Library
//anydd DD DSN=. DISP=SHR Optional input library
//SYSUT1 DD UNIT=SYSDA,SPACE=(TRK,(30)) Required work file
//SYSIN DD * Control Statements (optional)
control statements.
/*

Explanation of Linkage Editor JCL:
EXEC: PGM=HEWL or LINKEDIT can also be specified.

PARM: The optional PARM field is used to pass different processing
options. Possible PARM= values are described below under control
statement descriptions. Possible PARM field options are listed
here.

For load module attributes:

AC=n - Sets authorization code (1 if APF authorized)
DC - Sets downward compatible attribute by forcing a
maximum output blocksize of 1024 bytes
SCTR - Indicates "scatter" load module format
NE - Sets "not editable" attribute - module can't
be relinked
OL - Sets "only loadable" attribute
OVLY - Sets "overlay" attribute
RENT - Sets "reentrant" attribute if all CSECTS are
marked reentrant
REUS - Sets "serially reusable" attribute if all CSECTS
are marked serially reusable
REFR - Sets "refreshable" attribute if all CSECTS are
marked refreshable
AMODE=31|24|ANY - Sets addressing mode of load module(s)
RMODE=24 or ANY - Sets residency mode of load module(s)
TEST - TSO TEST command symbol tables are accepted as
input and are placed in the output module

For linkage editor execution options:

DCBS - When specified, allows the SYSLMOD DD
statement to specify DCB=
LIST - Produces a control card listing
LET | NOLET - Produce or don't produce executable module if
missing references
MAP | NOMAP - Do or don't produce load module map
XREF - Produce load module cross reference map
NCAL - Don't search SYSLIB to resolve missing external
references
XCAL - Allows valid exclusive calls not to be
considered an error and thus the load module
marked executable
PRINT | NOPRINT - Do or don't print messages to SYSLOUT DD
TERM - Write error messages to SYSTERM DD statement
SIZE=(v1,v2) - Specifies size of region and buffer used for
load module formatting. 'v1' is region size to
use, 'v2' is buffer size. Default for 'v1' is
256K, default for 'v2' is 48K. Optimum value
for 'v2' is 2 times SYSLMOD block size

SYSPRINT DD :
The SYSPRINT DD statement is required and must have RECFM=FBA or
RECFM=FB. The BLKSIZE value can be any value up to 32670 that
is a multiple of 121. Linkage editor messages are written to
this file.

SYSLIN DD :
The SYSLIN DD statement is required and contains the input for
the linkage editor. The input can be object modules output from
a compiler, or load modules from the linkage editor, or both.
The SYSLIN file must be a sequential file or a PDS member.
Linkage editor control statements can appear anywhere in the
SYSLIN input. The SYSLIN input can also consist of just control
statements.

SYSLIB DD :
The SYSLIB DD statement is optional and points to the 'auto-
call' library. The library must be a PDS that contains either
object modules or load modules but not both. More than one PDS
can be concatenated together.

External references are searched for in SYSLIB unless the NCAL
JCL parm is specified. External references are resolved from
the SYSLIB library if they exist as a member or alias in the
library and are marked as an external symbol in the external
symbol dictionary (ESD) of the member found.

SYSLMOD DD:
The SYSLMOD DD statement is required and points to the output
file which is to contain the load modules being built by the
linkage editor. The SYSLMOD file must be a PDS member or a PDS.
RECFM=U is forced by the linkage editor.

anydd DD:
Additional DD statements with any ddname can also be added to
the linkage editor JCL. These DD statements point to files that
will be processed by INCLUDE control statements.

Valid control statements for the linkage editor are ALIAS, CHANGE,
ENTRY, EXPAND, IDENTIFY, INCLUDE, INSERT, LIBRARY, MODE, NAME, ORDER,
OVERLAY, PAGE, REPLACE, SETCODE, and SETSSI. Control statement
operands can appear anywhere between columns 2 through 72. Control
statements are continued by ending the continued statement with a
comma, placing a non-blank character in column 72, and continuing the
statement beginning in column 16 on the next statement. The syntax
and usage of each is discussed below:

ALIAS:
The ALIAS statement is used to assign an alias for a load
module. Up to 64 aliases can be set for a load module and on
one ALIAS statement. The aliases being assigned are applicable
to the load module that will be named by the next NAME statement
in the input stream. The format of the ALIAS control statement
is:

ALIAS external name ,external name .

CHANGE:
The CHANGE statement is used to change an entry point name, an
external name, or a CSECT name in a load module to a new value.
Several such changes can be performed on one CHANGE statement.
The CHANGE statement affects the module that is next input,
either via SYSLIN directly or because of an INCLUDE statement.
The format of the CHANGE control statement is:

ENTRY:
The ENTRY statement assigns the main entry point for a load
module. The main entry point is the first instruction that will
be executed when the module is invoked. The entry point being
assigned is applicable to the load module that will be named by
the next NAME statement in the input stream. The format of the
ENTRY control statement is:

'entry-name' has to be a CSECT or an external entry point in the
module itself.

EXPAND:
The EXPAND statement causes the linkage editor to add extra
binary zero bytes to one or more CSECTS in a load module. The
number of bytes indicated on the EXPAND statement are added at
the end of the CSECT named by the EXPAND statement. The format
of the EXPAND control statement is:

'nnnn' is a decimal number indicating the number of bytes to add.

IDENTIFY:
The IDENTIFY statement allows you to add up to 40 characters of
identification information to the identification (IDR) record
for the CSECT(s) named on the IDENTIFY statement. The format of
the IDENTIFY control statement is:

Any 1 to 40 EBCDIC characters make up 'data-value'. A null value
is represented by a single blank.

INCLUDE:
The INCLUDE statement makes the linkage editor read additional
sequential files or PDS members. INCLUDE statements are used to
build a composite load module or modules from several different
component modules in one or several libraries. INCLUDE
statements are used in the same order that they are encountered
in the input stream. The format of the INCLUDE control
statement is:

'ddname' is the DD name of a JCL statement in the current job
step. 'memname' is the optional name of a PDS member that
resides in the PDS allocated to 'ddname'.

INSERT:
The INSERT statement makes the linkage editor move a CSECT from
where it is in the input stream to a segment in an overlay
structure. INSERT statements for CSECT to be placed in the root
segment should come before all OVERLAY statements. INSERT
statements for other segments must follow the OVERLAY statement
that names the segment the CSECT is to be inserted into. The
format of the INSERT control statement is:

LIBRARY:
The LIBRARY control statement is used to identify libraries in
addition to SYSLIB that are to be searched when resolving
external references. LIBRARY is also used to prevent a external
reference from being resolved during the current linkage editor
job step, or during any linkage editor job step. The format of
the LIBRARY control statement is:

LIBRARY {ddname(memname,memname. )},(ext-name),*(ext-name)

'ddname' is the DD name of a PDS that is to searched when
resolving external references; (memname,memname. ) lists the
members to be searched. '(ext-name)' identifies an external
reference that is not to be resolved during this linkage editor
step, and '*(ext-name)' identifies an external reference that is
never to be resolved. The LET parm should be specified when
LIBRARY is used to prevent external references from being
resolved.

MODE:
The MODE control statement is used to force an addressing and/or
residency mode for a load module. MODE overrides any value set
in the ESD CSECT entries or via the JCL PARM field. The format
of the MODE control statement is:

'mode' is either AMODE(24), AMODE(31), or AMODE(ANY) to set
addressing mode, and RMODE(24) or RMODE(ANY) to set residency
mode. AMODE and RMODE can both be set on one statement.

NAME:
The NAME statement is used to specify the name of a load module
being link edited. The module is stored in the SYSLMOD library
using the member name supplied on the NAME statement. The
format of the NAME control statement is:

'memname' is the member name the module is stored under; '{(R)}'
is an optional replacement indicator - if the module already
exists in the SYSLMOD library, then it will not be replaced
unless the '{(R)}' indicator is supplied. NAME should be placed
after all other control statements applicable to a given load
module.

ORDER:
The ORDER statement is used to arrange the common areas or
CSECTS in a load module into a specified sequence. The ORDER
statement should appear before the NAME statement and INCLUDE
statements it refers to. The format of the ORDER control
statement is:

The common area name 'name' or 'csectname' values supply the
names of the common area and CSECTS to be ordered; they are
ordered in the load module in the sequence that they appear on
the ORDER statement(s) for that module. The {(P)} value
indicates that the 'name' or 'csectname' before it is to reside
on a page boundary when the module is loaded for execution.

OVERLAY:
The OVERLAY statement is used to identify the start of an
overlay segment or region. The format of the OVERLAY control
statement is:

'symbol' is the symbolic name assigned to a segment and
'(REGION)' identifies the start of an overlay region.

PAGE:
The PAGE statement forces a given CSECT in the output load
module to be linked so that it is aligned on a 4K page boundary
when the module is loaded for execution. Binary zero filled
empty space is generated by the linkage editor, if necessary, to
force the boundary alignment requested. The PAGE statement
applies to CSECTs in the module that the next NAME statement
refers to. The format of the PAGE control statement is:

'name' is the common name and 'csectname' is the name of CSECT
to be page aligned. Multiple CSECTs can be listed on one PAGE
statement.

REPLACE:
The REPLACE statement is used to replace or delete a CSECT or
entry point name in a load module. The format of the REPLACE
control statement is:

'oldcsect' is the name of the CSECT being replaced or deleted.
'(newcsect)' is the optional new name of the CSECT. If the
'(newcsect)' value is omitted and just the 'oldcsect' is coded,
then the old CSECT is deleted from the output load module named
by the next NAME statement. Multiple CSECTs can be listed on
one REPLACE statement.

SETCODE:
The SETCODE statement sets the APF (Authorized Program Facility)
code for a load module. Certain MVS functions require that a
program have a non-zero APF code (zero is the default). The
format of the SETCODE control statement is:

'n' is a 1 to 3 digit APF authorization code ranging from 0 to a
maximum of 255. 'AC( )' sets the code to 0. Only the last one
of multiple SETCODE statements is used. SETCODE affects the
output load module named by the next NAME statement.

SETSSI:
The SETSSI statement is used to set System Status Information
(SSI) for the output load module. SETSSI sets an 8-digit
hexadecimal code in the output load module for tracking
purposes. The format of the SETSSI control statement is:

Where 'xxxxxxxx' is the 8-hex-digit SSI information to be stored
with the load module. If SETSSI is not used, not information is
stored with the load module.

Linkage Editor Usage Examples:

JCL to relink a program without linkage editor control statements:

//JS10 EXEC PGM=IEWL,REGION=1024K,
// PARM='LIST,MAP,XREF'
//SYSUT1 DD UNIT=SYSDA,
// SPACE=(CYL,(3,2))
//SYSPRINT DD SYSOUT=*
//SYSLMOD DD DSN=my.linklib(module),
// DISP=SHR
//SYSLIN DD DSN=my.object.lib(module),
// DISP=SHR

JCL to relink a program with linkage editor control statements:

Hope this helps.