On Sun, 29 Oct 2000, kason wong wrote:
> hi,
>
> I'm not sure this is the mail-list i should send my question. please
> let me know if I've got the right place.
>
> my problem is in the compiling a function in c++ to a .so lib file. the
> case is I use a couple static .a lib in that c++ program and when i
> compile it to a .so lib. it doesn't include the .a lib in it. i guess
> that's why I always get "undefined symbol" error when i execute the java
> program which call the c++ function.
>
> what can i do ? hope someone can give me some help here.
Here's a makefile I use for compiling a jni layer which
calls routines in *.a files. libsystem.a is the original library.
This gets converted to libsystem.so for use in the link step.
The final loadable library is libjsystem.so.
JNsApiSubsystemInterfaces.c and .h are the C JNI layers connecting
JNsApiSubsystemInterfaces.java to libsystem.o to become libjsystem.so.
Pay particular attention to the a.so suffix rule, and the sequence of
commands for building libjsystem.so toward the bottom. The ld and gcc
options are particularly important. The -shared is the key gcc option
and as such is hardwired in the command rather than being stored in
GCCOPT.
I use gcc, not g++, but the methods should be close to identical.
There may be other ways of doing this, but this is what I found works well
on my Red Hat system.
-------------------------------------------------------------------------
.SUFFIXES : .h .c .a .so .java .class
.a.so:
ld -shared -o $*.so --whole-archive $<
nm $*.so >$*.symbols
.java.class:
true
#
# location of JVM we're linking to
#
# Sun's 1.2.2
#
JAVA_HOME=/usr/local/java/jdk1.2.2
JAVA_INC= -I$(JAVA_HOME)/include -I$(JAVA_HOME)/include/linux
JAVAH=/usr/local/java/jdk1.2.2/bin/javah
#
# gcc configurable compile options
# -H list include header names
# -g debugging code enabled
GCCOPT= -g
LDOPT=-Xlinker -t -Xlinker -Map -Xlinker /tmp/linkmap -Xlinker -cref
GCCDEF=-DIP_SUPPORT -DUNIX
#
# Where the library.so file is written
#
LIBOUT=$(HOME)/lib
#
# These start as .a files, I have to convert them to
# shareable .so files for JNI to access them.
#
JAPILIBS=$(LIBOUT)/libjsystem.so
APISOLIBS= $(LIBOUT)/libsystem.so
APILIBS= $(LIBOUT)/libsystem.a
LINKLIBS=-L$(LIBOUT) -lnat -lsystem -ludpmsg -luser -lvoip -lc
#
# Project's root directory
#
PROJ=$(HOME)/jbproject/NSApi
#
# Project's source root and classpath root
#
SRC=$(PROJ)/src
CLASSES=$(PROJ)/classes
#
# base name of the library
#
LIBNAME=jsubsystem
#
# C Source files for gcc command
#
CSRC=$(SRC)/JNsApiSubsystemInterfaces.c
#
# Java Class files
#
JCLASSES= $(CLASSES)/com/aravox/nsapi/*.class \
$(CLASSES)/com/aravox/nsapi/subsystem/*.class
#
# all sources lib depends upon
#
ALLSRC= $(SRC)/*.h $(SRC)/*.c $(JCLASSES)
all: $(APISOLIBS) $(JAPILIBS) $(ALLSRC)
$(LIBOUT)/libjsystem.so: \
$(SRC)/JNsApiSubsystemInterfaces.h \
$(SRC)/JNsApiSubsystemInterfaces.c \
$(CLASSES)/com/aravox/nsapi/subsystem/JNsApiSubsystemInterfaces.class
- rm -f $@
@echo Creating $@...
gcc $(GCCOPT) $(GCCDEF) $(JAVA_INC) -I$(SRC) \
$(LDOPT) \
-shared -o $@ $(SRC)/JNsApiSubsystemInterfaces.c \
$(LIBOUT)/lib*.so
/home/joi/bin/anyUndefined $(LIBOUT)/lib*.so
$(SRC)/JNsApiSubsystemInterfaces.h:
$(SRC)/com/aravox/nsapi/subsystem/JNsApiSubsystemInterfaces.java
- ls -lart $(SRC)/com/aravox/nsapi/subsystem/JNsApiSubsystemInterfaces.java
$(SRC)/JNsApiSubsystemInterfaces.h $(SRC)/JNsApiSubsystemInterfaces.h
$(JAVAH) \
-classpath $(CLASSES) \
-o $(SRC)/JNsApiSubsystemInterfaces.h \
com.aravox.nsapi.subsystem.JNsApiSubsystemInterfaces
echo "$(SRC)/JNsApiSubsystemInterfaces.h regenerated";
$(SRC)/com/aravox/nsapi/JNsApiSubsystemInterfaces.java:
@echo "Nothing to do."
clean:
rm -f $(LIBOUT)/*.so
rm -f $(SRC)/JNsApiSubsystemInterfaces.h
-------------------------------------------------------------------------
--
Joi Ellis Software Engineer
Aravox Technologies [EMAIL PROTECTED], [EMAIL PROTECTED]
No matter what we think of Linux versus FreeBSD, etc., the one thing I
really like about Linux is that it has Microsoft worried. Anything
that kicks a monopoly in the pants has got to be good for something.
- Chris Johnson
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