Software Reference Manual - NetEx

RDDNAME DS CL8 DDNAME of file
RRPARM DS CL64 64 bytes of RPARM text
*
* Work area for use by the record module
*
RMSAVE DS 18F Save area for rtns called by Rmod
*
END RCRECMOD
Writing Block Modules
The block modules are also designed to be entered from a single entry point. They differ from the simpler
record modules specified above in several ways:
They take complete responsibility for providing and accepting blocks of information from NETEX. All
protocol needed by the block modules, such as record lengths or end of file indications, must be passed
from the sender to the receiver through the file buffer.
The block modules have total control over the NETEX DATAMODE parameter. They can set or examine
this value to send specialized data formats.
Unlike record modules, block modules cannot insert messages to be sent to the other side of the BFX
transfer process. If they want to send information along with the file data, it must be embedded in the file
protocol used by the block modules.
Block modules are almost exclusively reserved for applications that are moving binary data between dissimilar
hosts. In that case, custom DATAMODEs will often be needed to speed the work of converting floating
point numbers and the like. By giving the block modules total responsibility for protocol, any NETEX supported
DATAMODE may be used during the file transfer process.
IMPORTANT: When writing modules that call NETEX, it is important to clear the high byte of register
13 prior to calling NETEX. If a flag occupies this register when NXMUIFOO is called,
an abnormal termination will occur.
FORTRAN Entry
The entry to the block module should be declared as shown in Figure 19.
SUBROUTINE bmod (BUF,BUFLEN,BFUBIT,BDTMOD,
+ BUFLEV,MSG,MSGLEN,
+ MSGLEV,LCM,MODE,DDNAME,
+ BBPARM,RMOD,BRPARM)
type BUF(1)
INTEGER*4 BUFLEN,BFUBIT,BDTMOD,BUFLEV,MSGLEN
INTEGER*4 MSGLEV,LCM,MODE
CHARACTER*128 MSG
CHARACTER*64 BRPARM,BBPARM
CHARACTER*8 RMOD,DDNAME
Figure 19. Block module entry
The parameters in Figure 19 are described in the following paragraphs.
MAN-REF-H211-05 Appendix A: User Modules Page 71