File I/O statements and APIs

Enhancement reference: BZ#19156

IBM® Informix® 4GL version 7.50.xC4 introduced file manipulation instructions to access files on the operating system running the application. These instructions can be used to open, read, write, seek and close files:

MAIN
   DEFINE fd1, fd2 INTEGER, v1,v2 VARCHAR(10)
   OPEN FILE fd1 FROM "/tmp/file1" OPTIONS (READ, FORMAT="CSV")
   OPEN FILE fd2 FROM "/tmp/file2" OPTIONS (WRITE, APPEND, CREATE, FORMAT="CSV")
   READ FROM fd1 INTO v1, v2
   SEEK ON fd2 TO 0 FROM LAST INTO v1
   WRITE TO fd2 USING v1, v2
   CLOSE FILE fd1
   CLOSE FILE fd2
END MAIN

Genero Business Development Language (BDL) implements file I/O support with the base.Channel built-in class. This class implements file access, but it can also open streams to subprocesses (i.e. pipes) and sockets.