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File:          mkshlib-demo.tar.gz
Description:This package is an example to illustrate the subtleties of mkshlib
Keywords:      mkshlib
Version:       
Entered-date:   
Author:         
Ported-by:	
Original-site:	
Copying-policy:	CMU
Supplemental:

This package a contrived example to illustrate some of the subtleties
of mkshlib.   The following files should be found here:

	Makefile	- build the example.
	data.c		- exported data from the shared lib.
	imports.h	- macroes for imported data and code items.
	ex.h		- definitions of common data and functions.
	example.c	- main program for building ex1 & ex2.
	funcA.c		- a function which is placed in the shared lib.
	funcB.c		- a function which is placed in the shared lib.
	myfuncB.c	- a version of funcB to be statically linked.
	tlib.sl		- specification for building a shared library.

The features demostrated are:

- Defining a shared library function for use by client programs.
- Exporting data definitions from a shared library.
- Importing data (and code) definitions from a client program.
- Exporting and importing the same datum or code (ie. default).

testname and uname are defined in data.c.
These data items are both exported, which means clients of the
library can use them directly.
Uname is also imported.  This means that if a client defines
the symbol itself, the shared library will use it.
Imported data symbols cost one pointer dereference per use.
The symbol funcB() is available as a branch, and also imported.
If an application defines its own funcB (as is done in myfuncB.c),
the shared library will invoke it rather than the one bound to the
library.   This costs one pointer dereference per invocation.
The makefile builds three programs: ex1, ex2 and tlib.  The latter
is the target shared library.
ex1 redefines the symbols funcB, uname and testname. 
The expected output of ex1 is:

funcA.c: uname =ex1 testname = testname defined in data.c
myfuncB.c: uname =ex1 testname = testname, defined in myfuncB.c
myfuncB.c: uname =ex1 testname = testname, defined in myfuncB.c
example.c: uname = ex1 testname =testname, defined in myfuncB.c

Note that all modules are using a consistant uname, but the program
(example.c and myfuncB.c) have a different testname than funcA.c does.
Also note that when funcA invokes funcB, it is invoking the one the
program defined, not the one in the shared library.
ex2 uses only the shared library (ie. doesn't redefine any of the symbols)
and it's output is:

funcA.c: uname =ex2 testname = testname defined in data.c
funcB.c: uname =ex2 testname = testname defined in data.c
funcB.c: uname =ex2 testname = testname defined in data.c
example.c: uname = ex2 testname =testname defined in data.c



If you have any problems, I can be reached on quics as "steve",
or as "steve@qnx.com"
 
archive contents:

drwxrwxr-x  0 steve    techies 	         Jun 29 14:18 mkshlib-demo
-rw-rw-r--  0 steve    techies 	     509 Jun 29 14:18 mkshlib-demo/Makefile
-rw-rw-r--  0 steve    techies 	      91 Jun 29 11:51 mkshlib-demo/data.c
-rw-rw-r--  0 steve    techies 	      56 Jun 29 11:57 mkshlib-demo/imports.h
-rw-rw-r--  0 steve    techies 	     127 Jun 29 11:56 mkshlib-demo/ex.h
-rw-rw-r--  0 steve    techies 	     220 Jun 29 12:10 mkshlib-demo/example.c
-rw-rw-r--  0 steve    techies 	    1437 Jun 29 12:02 mkshlib-demo/funcA.o
-rw-rw-r--  0 steve    techies 	     608 Jun 29 12:02 mkshlib-demo/funcB.o
-rw-rw-r--  0 steve    techies 	     346 Jun 29 12:00 mkshlib-demo/funcA.c
-rw-rw-r--  0 steve    techies 	     427 Jun 29 12:02 mkshlib-demo/data.o
-rw-rw-r--  0 steve    techies 	     669 Jun 29 12:02 mkshlib-demo/myfuncB.o
-rw-rw-r--  0 steve    techies 	     153 Jun 29 12:00 mkshlib-demo/funcB.c
-rw-rw-r--  0 steve    techies 	    2547 Jun 29 14:17 mkshlib-demo/README
-rw-rw-r--  0 steve    techies 	     286 Jun 29 12:03 mkshlib-demo/tlib.sl
-rw-rw-r--  0 steve    techies 	     190 Jun 29 12:00 mkshlib-demo/myfuncB.c
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