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Hi Chris... Chris Bipes <ChrisB@cross-check.com> wrote: > > I am trying to add the ability to look up a service name using the > Getservbyname function. I have defined the data structure servent > with-in > my program but the pointer returned by the function is not to the da > structure I defined. How do you retrieve the entries from the memor > the > pointer is pointing to? I would imagine that the s_name start at th > pointer and goes to the first null, followed by list of aliases, eac > null > terminated. Then there should be the port number as a short integer > and > that is what I am looking for. I suppose I could just open the file > qusrsys/qatocls1 and chain to receive but that would be cheating.... > I am > carious as to see if anyone else has successfully used this function > > Christopher K. Bipes mailto:ChrisB@Cross-Check.com > Sr. Programmer/Analyst mailto:Chris_Bipes@Yahoo.com > CrossCheck, Inc. http://www.cross-check.com > 6119 State Farm Drive Phone: 707 586-0551 x 1102 > Rohnert Park CA 94928 Fax: 707 586-1884 Whats actually in the servent structure will be the pointer data, not a null terminated string. In other words, the pointer returned by getservbyname does not start with a null-terminated character string, but rather with the address of another area of memory. What makes it even more fun is the s_aliases subfield in the servent structure. Its not just a pointer, but a pointer to an array of pointers! (variable-length, too) The gethostbyname (which I use almost constantly) works the same way, so if you're familiar with that, maybe that'll help you :) Tell ya what, I'll include some example code (at the bottom of this message) that shows the use of the getservbyname function. (This code has been tested, and it works on my system...) Please keep in mind that these things ARE case-sensitive. In other words, if you use my example code, and do: CALL PGM(WHATEVER) PARM('telnet' 'tcp') This WILL work, but: CALL PGM(WHATEVER) PARM('telnet' 'TCP') this won't. The service is 'tcp' not 'TCP' Hope that helps... Scott Klement Information Systems Manager Klement's Sausage Co, Inc. Here's the sample code for the getservbyname function: -------------------------cut here------------------------------------ D MAX_ALIAS C CONST(50) D p_servent S * D servent ds based(p_servent) D s_name * D s_aliases * D s_port 10I 0 D s_proto * D alist S * DIM(MAX_ALIAS) BASED(s_aliases) D c_name S 50A BASED(s_name) D c_proto S 50A BASED(s_proto) D p_alias S * D c_alias S 50A BASED(p_alias) D ServByName PR * ExtProc('getservbyname') D service * value D proto * value C *entry plist c parm Service 20 c parm Protocol 20 c eval Service = %trim(service) + x'00' c eval Protocol = %trim(Protocol) + x'00' ************************************ ** Lookup the service ************************************ c eval p_servent = ServByName( %addr(Service) : c %addr(Protocol)) c if p_servent = *NULL c eval Msg = 'Lookup failed!' c dsply Msg 50 c eval *INLR = *ON c Return c endif ************************************ ** Show the name of the service ************************************ c x'00' scan c_name pos 3 0 c Select c when pos < 1 c eval Msg = 'Name=' + %Trim(c_name) c when pos = 0 c eval msg = 'Name=*BLANKS' c other c eval msg = 'Name=' + c %trim( %subst(c_name:1:pos-1) ) c endsl c msg dsply ************************************ ** Show the aliases of the service ** (if there are any) ************************************ c do MAX_ALIAS X 3 0 c if alist(X) = *NULL c Leave c endif c eval p_alias = alist(X) c x'00' scan c_alias pos 3 0 c Select c when pos < 1 c eval Msg = 'Alias=' + %Trim(c_alias) c when pos = 0 c eval msg = 'Alias=*BLANKS' c other c eval msg = 'Alias=' + c %trim( %subst(c_alias:1:pos-1) ) c endsl c msg dsply c enddo ************************************ ** Port Number (the easy one) ************************************ c move s_port wkPort 10 c '0' check wkPort pos c eval Msg = 'Port=' + %subst(wkPort:pos) c msg dsply ************************************ ** Finally, protocol.... ************************************ c x'00' scan c_proto pos 3 0 c Select c when pos < 1 c eval Msg = 'Prot=' + %Trim(c_proto) c when pos = 0 c eval msg = 'Prot=*BLANKS' c other c eval msg = 'Prot=' + c %trim( %subst(c_proto:1:pos-1) ) c endsl c dsply msg c eval *INLR = *ON c Return -------------------------cut here------------------------------------ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * This is the RPG/400 Discussion Mailing List! To submit a new * * message, send your mail to "RPG400-L@midrange.com". To unsubscribe * * from this list send email to MAJORDOMO@midrange.com and specify * * 'unsubscribe RPG400-L' in the body of your message. Questions should * * be directed to the list owner / operator: david@midrange.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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