IDS-UD External C Function detailed working example

Hello Everyone, I'm looking for a straight working example that starts from "A" and finished at the "Z" of creating, compiling, and using an external function written in "C" language on IDS-UD. It seems everywhere I go I stuck at some point or another, when I'm trying to build a small tiny example (like the volume calculation function found in the "Extending your database server with Informix Universal Server" training manual. I'm no expert in "C" but I'm trying to learn as much as needed to implement a few external functions. We have an IDS-UD version 9.13 running on Solaris 2.5.1 and we have the sun ANSI c compiler. Thanks for your help! Regards, Amgad Al-Sisi -----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own

amgad@starnet.com.eg wrote: : Hello Everyone, : I'm looking for a straight working example that starts from "A" and finished : at the "Z" of creating, compiling, and using an external function written in : "C" language on IDS-UD. Hope this kills two birds with one stone. This is a small useful example: a Soundex function. (Annoted) requested from another thread. But before I get too far into it, a couple of suggestions: 1. Use DBDK ( DataBlade Developer's Kit ). This generates all of the source stubs, header files and Makefiles for you. 2. Look in the $INFORMIXDIR/demo directory. You should find a couple of more comprehensive examples there. 3. Check out http://www.informix.com/idn, which contains a lot of working example code, along with tricks, tips and techniques. 4. Check out Sanchez, Angela. _Universal_Server_:_Best_Practices_ Prentice Hall. 1998. It contains a lot of examples that are good 'habits of thought'. OK. The procedure: 1: Write your 'C' code. The file here is called 'Soundex.c'. It's all you need for a phonetic match. Note that this is a pretty conventional algorithm. More exotic ones are probably more useful. Create $INFORMIXDUR/extend/Soundex/{src,bin,install} The Soundex.c and Makefile go in the src directory. The bin is where the Makefile puts the shared library. The install is a good place for the register.sql. /* * * File: soundex.c * * By: Paul Brown * * About: This implements the 'soundex' functionality. * * This is based on a version of the system I grabbed from a * bunch of 'C' functions on the 'net. * * There are lots of SAPI (Server API) notes scattered * through this piece. */ /* ** When you write your extension, you can generally make use of ** facilities from the standard 'C' libraries. There are a ** few exceptions, however. ** ** Also, ABSOLUTELY NO SYSTEM CALLS (malloc, free, open, write, etc). ** These cause confusion between the server process and the operating ** system. **/ #include <ctype.h> #include <stdio.h> #include <string.h> #include <stddef.h> /* ** All of the mi_* functions are stubbed in this header file, as are ** all of the SAPI types. These are universally available on the ** platforms IUS supports. ** **/ #include <mi.h> /* ** mi_lvarchar ('mi_' says 'this is a server data type, 'lvarchar' says ** that this is a variable length char array) is a general string ** literal type. That is, strings in queries are turned into this ** type. ** ** This function takes a single string as its only SQL argument, ** and returns a single string as its result. The MI_FPARAM * ** argument is an additional, server handle to conlvarchar information. **/ mi_lvarchar * soundex( mi_lvarchar * inlvarchar, MI_FPARAM * gen_fparam ) { /* ** For each 'C' type and each SQL built-in type, there is a ** corresponding SAPI type. For example, SQL INTEGERS and ** 'C' int are represented as mi_integer. SQL decimals are ** the dec_t type. 'C' uses NULL Terminated strings, whch are ** not really supported in SQL, but in SAPI are represented ** as mi_char (instead of char). **/ /* ABCDEFGHIJKLMNOPQRSTUVWXYZ */ mi_char *table = "01230120022455012623010202"; mi_integer count = 0; mi_lvarchar * outlvarchar; mi_char * instr, * outstro, * outstr; /* ** SAPI provides facilities for turning it's string representation ** into 'C' NULL terminated string. **/ instr = mi_lvarchar_to_string(inlvarchar); /* ** Most of the UNIX/POSIX system calls have SAPI equivalents. **/ outstro = (char *)mi_alloc(6); /* Always returns 6 characters */ outstr = outstro; while(!isalpha(instr[0]) && instr[0]) ++instr; /* ** This illustrates how to return a NULL result from a UDR. Simply ** handing back a '0' (NULL) isn't enough. The function might ** be returning either a 0 INTEGER value or a NULL. So this ** SAPI Call instructs the ORDBMS that the function has ** returned a NULL value. In this case, an exception might be ** more appropriate, but what is the sound of an empty string? ** **/ if(!instr[0]) /* Hey! Where'd the string go? */ { mi_fp_setreturnisnull( pfParam, 0, MI_TRUE ); return (mi_lvarchar *)NULL; } /* ** Note how all of this code works with NULL Terminated strings, ah la ** conventional 'C' programming. **/ if(toupper(instr[0]) == 'P' && toupper(instr[1]) == 'H') { instr[0] = 'F'; instr[1] = 'A'; } *outstr++ = (char)toupper(*instr++); while(*instr && count < 5) { if(isalpha(*instr) && *instr != *(instr-1)) { *outstr = table[toupper(instr[0]) - 'A']; if(*outstr != '0') { ++outstr; ++count; } } ++instr; } *outstr = '\\0'; /* ** And this turns the NULL terminated string into an mi_lvarchar for a ** return result. **/ return(mi_string_to_lvarchar(outstro)); } /* END */ 2. Compile your code. In general, I would really recommend the Makefiles that DBDK generates. If you look at the WinNT.mak, you can even figure out how to configure VC++ or Borland. Put this in a file called 'Makefile' in the same directory as the Soundex.c. And make sure that you have a ../bin directory created. When you use this makefile, you will obviously have to change the compiler (I use gcc and fully spec the path out of bad habit). NOTE: The sharedlibrary you create (Soundex.bld) must be owned by 'informix', and it must not be writeable by other users. In other words, run this makefile as 'informix' #-- BEGIN -- # This is the project title. PROJECT_TITLE= Soundex # TARGET must be set to the location/filename # of the platform-specific make include file. # include $(INFORMIXDIR)/incl/dbkd/$(TARGET).mak # MI_INCLUDE=$(INFORMIXDIR)/incl RM= rm RMFLAGS= -f # CC= /usr/ucb/cc # CC= /opt/SUNWspro/SC3.0/bin/cc -g CC= /usr/local/gnu/bin/gcc -g CSRVRFLAGS= -DMI_SERVBUILD # not for gcc, but OK for other -KPIC CFLAGS= $(CSRVRFLAGS) -I$(MI_INCLUDE)/public -I$(MI_INCLUDE)/esql -I$(MI_INCLUDE ) $(COPTS) LINK= /usr/ccs/bin/ld LINKFLAGS= -dy -G -Bsymbolic LIBS= -ldl -lnsl -lsocket -lm -lrpcsvc -lc DATABLADE_LIBS= SHLIBSUFF= bld BINDIR= ../bin # Platform independent code goes here. # The following code was generated by BladeSmith. PROJECT_OBJS= $(BINDIR)/$(PROJECT_TITLE).o all: server client # Construct the object file. $(BINDIR)/$(PROJECT_TITLE).o : $(PROJECT_TITLE).c $(CC) $(CFLA