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Torben Bang Nielsen  tbn@csd.cri.dk   (query)

Lately I've been playing around with loading .o files into an already
running program under SunOS 4.1.  I've found a set of functions
(dlopen, dlsym, dlclose and dlerror) which, according to the man-page,
should provide a convienient interface to the dynamic linker 'ld.so'
for dynamically linking object files into a program at run-time - not
load time.

Basically what must be done in order to achieve this is to prepare the
.o file with the '-A' option to the link editor 'ld' for run-time
linking (BTW all the C files should be compiled with the -pic option,
according to Sun's manual on shared libraries)

When the .o file have been prepared it should simply be a matter of
calling 'dlopen' from within the main program with the name of the .o
file as argument.  This is where it starts going wrong.  I get the
following error message from within the 'dlopen' function and the
program exits (with status code 127):

        ld.so: mmap data error (22) for test.o

What have I done wrong!?

The .o file was 'prepared' for loading into the executable 'dynload'
from a file 'test1.o' with the following command:

ld -assert pure-text -o test.o -A dynload -dp -dc test1.o

BTW the '-assert' didn't cause any messages.

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