Re: Named pipes?

On Wed, 9 Sep 1998, Florin Micle wrote: > Here is my problem: > > I want to send data to a C++ program. I would like to know if there is a > mechanism like named pipe in Oracle (DBMS_PIPE.SendMessage()) > Is there a way to do such things in Informix? Any other possibilities? > I mention that I have: Informix SE 7.02 (no ESQL/C) and use a GNU ^^^^ 7.20? > compiler with C++ libraries. I'm very new in working in Unix environment, so > bare with me :-). What sort of program do you want to use to get the data from the database? Since you don't have ESQL/C, you are probably planning to use DB-Access. You can arrange for your C++ program to start DB-Access with the correct argument list and for it to write SQL statements to the standard input of DB-Access and to read responses on the standard output of DB-Access. You'd probably do this with either a pair of pipes (good old-fashioned anonymous pipes) or a socket (which should provide bi-directional communications, IIRC) -- I'm old fashioned. You'd have to parse the output from DB-Access which would not be as easy as you'd like. Alternatively, you do more or less as Peter suggested and arrange to UNLOAD data to a file which happens to be a named pipe. You can then arrange for your C++ program to open the named pipe and read the data. mkfifo fifo dbaccess stores7 - <<! & UNLOAD TO "fifo" SELECT * FROM Customer; ! sleep 30 cat fifo If you want to get fancier, you are going to need ESQL/C, somewhere along the line. Your options are then much greater. If you really want to do things with named pipes, then the SQLCMD program in the IIUG archives has a mode which handles named pipes for input and output, or you can write your own program. Or you can embed the ESQL/C code directly into your C++ program. Or ... Yours, Jonathan Leffler (jleffler@informix.com) #include <witticism.h> Guardian of DBD::Informix v0.60 -- http://www.perl.com/CPAN Informix IDN for D4GL & Linux -- http://www.informix.com/idn