Weird behavior in CALLP vs. CALLB (specifically QtmmSendMail) -- RPG400-L

I'm experiencing a weird problem, with a call that workedas a CALLB suddenly NOT working with a CALLP.

Given this code (and note that I've pulled out a fewspaces here and there to try and keep my email reader frominserting line breaks):


DFILENAME         S             43
DFILENAMELENGTH   S              9B 0
DORIGINATOR       S            255
DORIGINATORLEN    S              9B 0
DFIRSTRECIPIENT   DS
D OFFSET                  1      4B 0
D ADDRLEN                 5      8B 0
D FORMAT                  9     16
D DTYPE                  17     20B 0
D RESERVED               21     24B 0
D RECADDRESS             25    275
DTOTALNUMREC      S              9B 0

DERRORMESSAGE     DS
D BYTESBUF                1      4B 0
D MESSAGEID               9     15
. . .
C                   EVAL      FILENAME =

C '/wintouch/WTCPCHILD JAMESL 146826115623'

C                   Z-ADD     43            FILENAMELENGTH

with BYTESBUF set to zero, so that any error will throw anexception, this code:


C                   CALLB     'QtmmSendMail'
C                   PARM                    FILENAME
C                   PARM                    FILENAMELENGTH
C                   PARM                    ORIGINATOR
C                   PARM                    ORIGINATORLEN
C                   PARM                    FIRSTRECIPIENT
C                   PARM                    TOTALNUMREC
C                   PARM                    ERRORMESSAGE

works fine, but this code (bytesbuf still zero, and lotsof spaces still pulled out to avoid unwanted line breaks):

D QtmmSendMail PRExtProc('QtmmSendMail')D FileName 255A constoptions(*varsize)

D   FileNameLen                10I 0 const

D MsgFrom 256A constoptions(*varsize)

D   MsgFromLen                 10I 0 const
D   RecipBuf                         like(FIRSTRECIPIENT)
D                                    dim(32767)
D                                    options(*varsize)
D   NumRecips                  10I 0 const
D   ErrorCode                8000A   options(*varsize)
. . .

C CALLP QtmmSendMail(FILENAME:FILENAMELENGTH:

C                               ORIGINATOR: ORIGINATORLEN:

C FIRSTRECIPIENT:TOTALNUMREC:

C                               ERRORMESSAGE)

doesn't work, doesn't throw an exception in the callingprogram, but causes the QMSF job to throw a TCP5103,claiming that it can't open the IFS file (the name isfine) with an errno of 3440 (something about "operationnot supported," according to errno_h).


To coin a phrase,
<tiny voice>
"Heellllllllppppppppppp mmmmmmmeeeeeeeeeeeeeee!!!"
</tiny voice>

--
JHHL