*Entry Plist w/ data structure using prototype / procedure interface

I'm writing my first trigger program in 15 or so years. I'm trying to
avoid the *Entry Plist C specs, but numerous attempts at defining the
prototype / procedure interface have not succeeded. The first parameter
for a trigger program is the buffer data structure. Obviously, I'm trying
to achieve best performance by not moving data around unnecessarily, so I'd
like to avoid moving the *entry parameters and, instead, use them directly.

We're on v7r1.

I've searched and haven't found any complete examples of how to do this in
/free. If anyone can provide a link or a RTFM reference, I would be most
appreciative.

5+d TrgBuffer ds
6+d tbFileName 10
7+d tbLibraryName 10
8+d tbMemberName 10
9+d tbEvent 1
10+d tbTime 1
11+d tbCommitLock 1
12+d tbFill01 3
13+d tbCCSID 10i 0
14+d tbRRN 10i 0
15+d tbFill02 10i 0
16+d tbOldOffset 10i 0
17+d tbOldLength 10i 0
18+d tbOldNullOff 10i 0
19+d tbOldNullLen 10i 0
20+d tbNewOffset 10i 0
21+d tbNewLength 10i 0
22+d tbNewNullOff 10i 0
23+d tbNewNullLen 10i 0
24+
25+d TrgBufferLen s 10i 0
26 d EntryParms pr ExtPgm( 'TRG001R'
)
27 d p1 Like( TrgBuffer
)
28 d p2 Like( TrgBufferLen
)
29 d EntryParms
pi
30 d
TrgBuffer
======>
aaaaaaaaa
======>
bbbbbbbbb
*RNF3316 30 a 000700 The item has already been defined on a
Definition
Specification; specification is
ignored.
*RNF3438 30 b 000700 LIKE keyword is expected for field but not
found;
definition is
ignored.
31 d
TrgBufferLen
======>
aaaaaaaaaaaa
*RNF3316 30 a 000800 The item has already been defined on a
Definition
Specification; specification is
ignored.
*RNF3438 30 31 000800 LIKE keyword is expected for field but not
found;
definition is
ignored.

- Dan