DDM reply messages are returned to the source system and include a server diagnostic area (SRVDGN). Normally, source errors do not cause a dump. SYNTAXRM and PRCCNVRM reply messages indicate DDM data stream errors; these errors might be a by-product of hardware or software (other than the end user). Accordingly, this error record is placed in the system LOGREC file. However, if it is deemed necessary to dump Distributed FileManager/MVS at the time of building a specific reply message, it is possible to set a SLIP trap. The SLIP trap forces a SVCD dump.

Because only one PER SLIP trap can be set at a time, you need to determine which Reply Message Builder is invoked (GDEHRBRM or GDEGBRMB). In the case of SYNTAXRM and PRCCNVRM, the system LOGREC record tells you the name of the invoked Reply Message Builder. Otherwise, examine the original reply message SRVDGN to determine the subcomponent/module calling for a reply message.

For a description of the mapping for the server-diagnostic-information fields, see . The first two bytes of the Distributed FileManager/MVS reason code identify the subcomponent/module that is requesting the reply message. The Communication Manager modules (GDEGxxxx) use GDEGBRMB; all other modules use GDEHRBRM. (The Communication Manager Modules are identified by subcomponent/module identification X'5516'- X'5529'.) If you are unable to examine the original SRVDGN, and it is not a SYNTAXRM or PRCCNVRM, most likely the invoked message builder is GDEHRBRM.

//A EXEC PGM=AMBLIST
//SYSPRINT DD SYSOUT=*
//SYSLIB DD DISP=SHR,DSN=SYS1.LPALIB
//SYSIN DD *
 LISTLOAD OUTPUT=XREF,MEMBER=GDEIGCA

To find the correct offset module, examine the AMBLIST output listing in Figure 1. The following excerpt from a sample AMBLIST listing shows that the offset of GDEGBRMB is X'9978' for the load module GDEIGCA. The offset of GDEHRBRM isX'434C8'.

Figure 1. Sample AMBLIST listing.

The next thing you need to know for the SLIP trap is the field offset; the offset indicates the type of reply message.

For GDEGBRMB, the macro to consult is GDEGRMB; the field is GRMB_MSG_CP. The GRMB_MSG_CP is at offset X'18' in the GDEGRMB. This field contains the DDM codepoint value: For example, SYNTAXRM is X'124C'.

The following example shows the SLIP command to cause a SVCD dump when the command enters GDEGBRMB (as in GDEIGCA,9978). The matching condition is that the input request in GDEGRMB at offset X'18', as in ( 1R?+4??+18), is to build a SYNTAXRM (EQ,0000124C).

SLIP SET,IF,LPAMOD=(GDEIGCA,9978),DATA=(1R?+4??+18,EQ, 0000124C),

JOBNAME=GDEDFM,ACTION=SVCD,ID=DFM1,END

For GDEHRBRM, the macro to consult is GDEHMPL. The field is HMPL_MSG_INDEX. This field does not contain the DDM codepoint, but the message index (defined in GDEHMPL, for example, HYMPL_SYNX) is constant (46, X'2E').

The following example tells the SLIP command to cause a SVCD dump when the command enters GDEHRBRM (as in GDEIGCA,434C8). The matching condition is that the input request in GDEHMPL at offset X'10', as in ( 1R?+4??+10), is to build a SYNTAXRM (EQ,002E)

SLIP SET,IF,LPAMOD=(GDEIGCA,434C8),DATA=(1R?+4??+10,EQ,002E),

JOBNAME=GDEDFM,ACTION=SVCD,ID=DFM2,END