Linking issues while compiling a simple c++ module in HP-UX

Biswadeep · ‎07-16-2014

We are trying to build a simple c++ module in hpux and deploy it in Apache httpd server.

Out tech stack consists of

HP-UX B.11.31 U ia64

aCC compiler for C++

Apache 2.2.27

We installed apache using the following steps

Step 1: export CFLAGS="+DD64"

Step 2: export CPPFLAGS="+DD64"

Step 3: ./configure CC=aCC --enable-mods-shared=most

Step 4: make

Step 5: make install

compilation command:

apxs -a -c -S cc=aCC -L/usr/lib/hpux64 -lstd_v2 -lCsup -lunwind -lm calculator.cpp

Then the ".so" is created in .libs directory.

Then we used the command:

nm calculator.cpp| grep UNDEF

we are getting undefined symbols mentioned below:

[0] | 0| 0|NOTYP|LOCAL|0| UNDEF|

[61] | 0| 0|FUNC |GLOB |0| UNDEF|_Unwind_Resume

[54] | 0| 0|FUNC |GLOB |0|UNDEF|_ZNSt8ios_base4InitC1Ev

[53] | 0| 0|FUNC |GLOB 0| UNDEF|_ZNSt8ios_base4InitD1Ev

[51] | 0| 0|FUNC |GLOB |0| UNDEF|_ZdlPv

[52] | 0| 0|FUNC |GLOB |0| UNDEF|_Znwm

[63] | 0| 0|FUNC |GLOB |0| UNDEF|__cxa_atexit

[57] | 0| 0|FUNC |GLOB |0| UNDEF|__cxa_finalize

[65] | 0| 0|FUNC |GLOB |0UNDEF|__cxa_personality_routine

[62] | 0| 0|FUNC |GLOB |0| UNDEF|ap_hook_handler

[60] | 0| 0|FUNC |GLOB |0| UNDEF|ap_rprintf

[55] | 0| 0|FUNC |GLOB |0| UNDEF|ap_rputs

[64] | 0| 0|FUNC |GLOB |0| UNDEF|strcmp

Hence we are unable to successfully deploy our service in apacheserver.

When we are trying to load the ".so" module in apache server we are geting these unsatisfied symbol and hence the apache server was unable to start.

The .so module that is created is not getting linked properly and hence we are facing these issues.

Any valuable help from your side would be highly appreciated.

Waiting for a reply soon,

Biswadeep Khan

P.S. This thread has been moved from General to HP-UX > languages. - Hp Forum Moderator

SoumitraC · ‎07-16-2014

I see several issues with your attempt.

First of all, you should not be setting 'CC' to point to the C++ compiler. You should instead point it to '/opt/ansic/bin/cc', which is the C compiler. You should instead set the 'CXX' variable to point to the C++ compiler '/opt/aCC/bin/aCC'.

Secondly, for generating shared libraries, you should be using the '-b' compiler option. I don't see this in the compilation command line you have provided.

Note that for C++ compilations, you must use the C++ compiler as the linker, and not directly use the linker. Typically, it is done by setting the 'LD' environment variable to point to the C++ compiler as well.

Soumitra C
HP-UX Compilers

Biswadeep · ‎07-16-2014

I tried specifying CXX=aCC but while building apache in the following confuguartion step

"./configure CXX=aCC --enable-mods-shared=all"

but in configure step of apache there is no option of specifying "CXX" as a parameter.It only takes "CC" as parameter.

Morover in our compilation command:

apxs -a -c -S CC=aCC calculator.cpp

if i m using the command:

apxs -a -c -S CXX=aCC -L/usr/lib/hpux64 -lstd_v2 -lCsup -lunwind -lm calculator.cpp

it is giving error that CXX is unknown option with apxs binaries.

Please help

Lastly I could not clearly understand the last point that you mentioned regarding "LD environment path " and c++ linker and compiler.It would be really helpful if you could elaborate this point clearly with the help of an example?

SoumitraC · ‎07-16-2014

Unfortunately, I don't have the apache package handy to be more precise.

BY 'LD', I meant if this also invokes the linker, then you must ensure that it does not invoke the linker directly. It must invoke the C++ compiler for the linking. Usually, this is controlled by the 'LD' environment variable (similar to the 'CC' environment variable).

Are you saying that you have manually inserted the options "-L/usr/lib/hpux64 -lstd_v2 -lCsup -lunwind -lm"? If so, you must remove them as these are automatically inserted by the compiler driver as required and in the correct order.

If you haven't already, you should go through the documentation on creating shared libraries at:

http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/HTML/libs.htm#createlib

Soumitra C
HP-UX Compilers

Biswadeep · ‎07-16-2014

I tried compiling a simple c++ code in aCC and build its ".so" without using apache.

The code is:

#include <float.h>

#include <string.h>

#include<iostream.h>

class calcService

{

public:

int add(double a, double b, double *result);

int sub(double a, double b, double *result);

};

int calcService::add(double a, double b, double *result)

{

*result = a + b;

return *result;

}

int calcService::sub(double a, double b, double *result)

{

*result = a - b;

return *result;

}

int main()

{

calcService calc;

return 0;

}

compilation command :

aCC -b +DD64 -AA -mt +z -L/usr/lib/hpux64 -o calc.so calculator.cpp

then we used the command

nm calc.so | grep UNDEF

[0]      |                     0|       0|NOTYP|LOCAL|0|   UNDEF|
[48]     |                     0|       0|FUNC |GLOB |0|   UNDEF|_Unwind_Resume
[45]     |                     0|       0|FUNC |GLOB |0|   UNDEF|_ZNSt8ios_base4InitC1Ev
[44]     |                     0|       0|FUNC |GLOB |0|   UNDEF|_ZNSt8ios_base4InitD1Ev
[50]     |                     0|       0|FUNC |GLOB |0|   UNDEF|__cxa_atexit
[46]     |                     0|       0|FUNC |GLOB |0|   UNDEF|__cxa_finalize
[51]     |                     0|       0|FUNC |GLOB |0|   UNDEF|__cxa_personality_routine

Even in a simple c++ code without using any apache header I am getting these undefined symbol.

My environment variable is set as below:

CXX=aCC -mt +DD64
CXX_SLD=aCC -mt +DD64
CXX_EXELD=aCC -mt +DD64
CXX_EXELDFLAGS=-mt -Wl,+vshlibunsats -Wl,+s -Wl,-Bimmediate -Wl,-E -o
CC=/opt/aCC/bin/aCC
CC_ANSI_ORIG=cc -mt +DD64
CC_ANSI=aCC -mt +DD64
SLCC=cc -mt -Wl,+s +DD64 +W 474,2174,2177,2550 -Aa -c
EXELDLIBS=-lm
EXELDFLAGS=-Wl,+vshlibunsats,+s,+n,-Bimmediate,-Bnonfatal -o
EXELD=cc -mt -Wl,+s +DD64 +W 474,2174,2177,2550
LD_LIBRARY_PATH=/opt/oracle/product/11g_client/lib
SLD=ld

please help how to get rid of these undefined symbol

Dennis Handly · ‎07-17-2014

>how to get rid of these undefined symbol

These are defined in other shlibs. If you are dynamically loading from a C program, then you need to supply these shilbs on the link line:

-lstd_v2 -lCsup -lunwind

http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/HTML/distributing.htm#linking

>-L/usr/lib/hpux64

Leave this off, supplied by linker.

>these are automatically inserted by the compiler driver as required and in the correct order.

Not when you create shlibs with -b. See above for a better reference.

Biswadeep · ‎07-17-2014

>Leave this off, supplied by linker

If I am not specifying lib path as "-L/usr/lib/hpux64" then by default it goes to the path "-L/usr/lib/hpux32". But we need to build it on 64 bit so we are specifying path as "-L/usr/lib/hpux64"

Secondly as per your instruction I tried running the following command

aCC -b +DD64 -AA +z -c -L/usr/lib/hpux64 -lstd_v2 -lCsup -lunwind calculator.cpp

aCC -b -o calc.so calculator.o

but then I checked with the ldd and nm command as follows:

ldd -d -r calc.so

calc.so:

symbol not found: _ZNSt8ios_base4InitD1Ev (./calc.so)

symbol not found: _ZNSt8ios_base4InitC1Ev (./calc.so)

symbol not found: __cxa_finalize (./calc.so)

symbol not found: _Unwind_Resume (./calc.so)

symbol not found: __cxa_atexit (./calc.so)

symbol not found: __cxa_personality_routine (./calc.so)

nm calc.so|grep UNDEF

[0] | 0| 0|NOTYP|LOCAL|0| UNDEF

| [48] | 0| 0|FUNC |GLOB |0| UNDEF|_Unwind_Resume

[45] | 0| 0|FUNC |GLOB |0| UNDEF|_ZNSt8ios_base4InitC1Ev

[44] | 0| 0|FUNC |GLOB |0| UNDEF|_ZNSt8ios_base4InitD1Ev

[50] | 0| 0|FUNC |GLOB |0| UNDEF|__cxa_atexit

[46] | 0| 0|FUNC |GLOB |0| UNDEF|__cxa_finalize

[51] | 0| 0|FUNC |GLOB |0| UNDEF|__cxa_personality_routine

I am still getting these same unsatsified symbols.

please help

SoumitraC · ‎07-17-2014

As Dennis clarified, the unsatisfied symbols are defined in the system libraries, which will be resolved once you link your shared library into the main program. There's no need for the symbols to be available in your shared library.

As regards the linker search path, the compiler option +DD64 specifies a 64-bit build, so you need not specify the -L explicitly.

Soumitra C
HP-UX Compilers

Biswadeep · ‎07-17-2014

As per my understanding of your statement the unsatisfied symbol in the ".so" gets resolved when we link the ".so" with any main program.

But in our case as we trying to deploy the code in apache, so our next step is not linking the .so file with any main program but to load the ".so" in apache server as a module.

so we are loading the ".so" in apache httpd.conf file using

LoadModule calc_module modules/calculator.so

the unsatisfied symbol in the ".so" should be resolved by apache while deploying it in server but it does not get resolved and when we start the server using the command

apachectl start(command to start the server)

it fails to start and gives the error: unable to start the server because of the unsatisfied symbols present.

So please help what we should do now.

Thanks

Dennis Handly · ‎07-17-2014

> by default it goes to the path -L/usr/lib/hpux32.

Who are you going to believe? You or an expert? :-)

>aCC -b +DD64 -AA +z -c -lstd_v2 -lCsup -lunwind calculator.cpp

>aCC -b -o calc.so calculator.o

-c overrides -b. Put the libs on the second line:

aCC +DD64 -c -AA +z calculator.cpp

aCC +DD64 -b -o calc.so calculator.o -lstd_v2 -lCsup -lunwind -lm

> nm calc.so | grep UNDEF

nm(1) is not the proper tool with dealing with shlibs.

>I am still getting these same unsatsified symbols.

You didn't link with those shlibs. Did you read the webpage about:

Linking Your HP aC++ Libraries with Other Languages

>which will be resolved once you link your shared library into the main program.

This is being dynamically loaded so needs those dependent shlibs are linked into the shlib.

>next step is not linking the .so file ... but to load the ".so" in apache server as a module.

Right.

>what we should do now.

Follow the directions on:

http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/HTML/distributing.htm#linking

Biswadeep · ‎07-23-2014

Thanks for all the help provided by you.

It was really helpful.

I was able to build the webservice in C++ and generate the "calc.so" using the below steps and load it in apache server successfully and now facing some issue while calling it through the client.

aCC +DD64 -c -AA +z calculator.cpp----(1)

aCC +DD64 -b -o calc.so calculator.o -lstd_v2 -lCsup -lunwind -lm------(2)

We are using another shared library as a load module(example-abc.so) and that library is written in C.which is getting linked with the webservice shared library generated by us through (2) i.e calc.so (in C++ as described above) at run time.

The same webservice("calc.so") written and generated in C gets linked with the load module shared library(abc.so) is successfully deployed and tested using client.

can someone help me how to resolve this issue.

Dennis Handly · ‎07-23-2014

>We are using another load module (abc.so) which is getting linked with ... calc.so at run time.

You are loading abc.so fron calc.so?

What's the error you're getting? What doesn't work?

Biswadeep · ‎07-23-2014

Hi

I am building a C++ webservice using a C++ webservice toolkit called gSOAP.

For this, we have to build two shared libraries -

1. Shared library for our actual webservice (e.g. calculator.so) which is loaded into Apache server. I generated the "calculator.so" using the below steps and load it in apache server successfully.

aCC +DD64 -c -AA +z calculator.cpp soapC.cpp soapcalcService.cpp stdsoap2.cpp

aCC +DD64 -b -o calculator.so calculator.o soapC.o soapcalcService.o stdsoap2.o -lstd_v2 -lCsup -lunwind -lm

2. Shared library for a Apache module provided by the gSOAP toolkit called mod_gsoap.so. We need to build this shared library uisng the code (mod_gsoap.c written in pure C language) provided in the toolkit. mod_gsopa.so is generated using the following command (where apxs is a "C binary" of apache server)

apxs -a -i -c mod_gsoap.c

After building the the above two modules, we loaded the modules in Apache server. Then we started the Apache server and server was able to start.

We have also created a client (calcclient.cpp) to call the calculator webservice deployed in Apache.

But when we run the client:calcclient add 2 3

we are getting the following error.

Error -1 fault: SOAP-ENV:Client[no subcode]

"End of file or no input: Operation interrupted or timed out"

Detail: [no detail]

I then tried bulding the mod_gsoap.so through aCC compiler instead of apxs using the following command:

aCC +DD64 -c -AA +z mod_gsoap.c

aCC +DD64 -b -o mod_gsoap.so mod_gsoap.o

and loaded the mod_gsoap.so into Apache but I get the same error after running the calcclient.

But, when we build the same calculator.so and mod_gsoap.so shared libraries using C compilation, the calcclient runs successfully.

what is the reason that the code does not work in C++?

SoumitraC · ‎07-23-2014

Name mangling, perhaps?

You may want to verify that the symbols being crossed referenced do not get mangled, which would cause it to appear missing.

Soumitra C
HP-UX Compilers

Biswadeep · ‎07-23-2014

Hi,

The following is our c++ calculator service code

calculator.cpp

extern "C"

{

#include "apache_gsoap.h"

} #include<iostream.h>

extern "C"

{

IMPLEMENT_GSOAP_SERVER()//Macro present in apache_gsoap.h

}

extern "C" int soap_serve(struct soap *soap) {

soap_init(soap);

calcService service(soap);

int err = service.serve();

service.destroy();

return err;

} int calcService::add(double a, double b, double *result)

{

*result = a + b;

return SOAP_OK;

}

int calcService::sub(double a, double b, double *result)

{

*result = a - b;

return SOAP_OK;

}

The apache_gsoap.h file is as folows:

#ifdef __cplusplus

extern "C"

{

#endif

--

--- IMPLEMENT_GSOAP_SERVER()/ ---//Code snnipet in "C" -- --

--

#ifdef __cplusplus

}

The mod_gsoap.c file needed to generate the other module mod_gsoap.so is as follows:

#ifdef __cplusplus

extern "C"

{

#endif

-

--- -- -- --
#ifdef __cplusplus

}

#endif
#endif

So i guess there is no issue with name mangling as the C code is written with extern "C" code.

Dennis Handly · ‎07-24-2014

>we are getting the following error.

Error -1 fault: SOAP-ENV:Client[no subcode]

"End of file or no input: Operation interrupted or timed out"

A particularly useless error.

>when we build the same calculator.so ... using C compilation

How can you do that when your source is C++?

>what is the reason that the code does not work in C++?

Have you tried setting breakpoints to trace the flow of code? You may have to use tusc.

>int err = service.serve();

I assume serve() is dispatching to your calcService member functions?

extern "C" {

#include "apache_gsoap.h"

}

Since apache_gsoap.h has already been C++ified, you shouldn't put it in another extern "C" block.

Biswadeep · ‎07-25-2014

Hi ,

Thanks for the updates and all the helps till now.

>when we build the same calculator.so ... using C compilation

How can you do that when your source is C++?

-->The source is in pure "C" ( not in C++) when we are using C compiler.

>what is the reason that the code does not work in C++?

Have you tried setting breakpoints to trace the flow of code? You may have to use tusc.

-->

we can not use tusc on a shared library , our service is .so so we have tried tusc with the client code (which is actually calling the service).

The output of tusc on client code is inconsistant on different executions.

We have tried the same tusc for the service written in "C" as well just to compare the output and below is the difference we observed at the end of the output generated by tusc:

In C:

send(4, "P O S T   / s o a p   H T T P / ".., 608, 0) ........................................................ = 608
recv(4, "H T T P / 1 . 1   2 0 0   O K \r".., 65536, 0) ...................................................... = 610
brk(0x6000000000034000) ...................................................................................... = 0
shutdown(4, SHUT_RDWR) ....................................................................................... = 0
close(4) ..................................................................................................... = 0
write(1, "a f t e r   c a l l   t o   A d ".., 18) ........................................................... = 18
write(1, "\n", 1) ............................................................................................ = 1
brk(0x6000000000036000) ...................................................................................... = 0
ioctl(1, TCGETA, 0x87fffffffffcc410) ......................................................................... = 0
write(1, "r e s u l t   a c t u a l   =   ".., 18) ........................................................... = 18
exit(0) ...............................

In C++

send(4, "P O S T   / s o a p   H T T P / ".., 608, 0) ........................................................ = 608
recv(4, "H T T P / 1 . 1   2 0 0   O K \r".., 65536, 0) ...................................................... = 894
recv(4, 0x87fffffffffd8680, 65536, 0) ........................................................................ = 0
write(1, "a f t e r   c a l l   t o   A d ".., 18) ........................................................... = 18
write(1, "\n", 1) ............................................................................................ = 1
write(1, "S O A P   E R R O R : ", 11) ....................................................................... = 11
write(1, "\n", 1) ............................................................................................ = 1
write(1, "R e s u l t 2 : ", 8) .............................................................................. = 8
write(1, "0 ", 1) ............................................................................................ = 1
write(1, "\n", 1) ............................................................................................ = 1
write(2, "E r r o r   ", 6) .................................................................................. = 6
write(2, "- 1 ", 2) .......................................................................................... = 2
write(2, " f a u l t :   ", 8) .............................................................................. = 8
write(2, "S O A P - E N V : C l i e n t ", 15) ............................................................... = 15
write(2, "[ ", 1) ............................................................................................ = 1
write(2, "n o   s u b c o d e ", 10) ......................................................................... = 10
write(2, "] ", 1) ............................................................................................ = 1
write(2, "\n", 1) ............................................................................................ = 1
write(2, "" ", 1) ............................................................................................ = 1
write(2, "E n d   o f   f i l e   o r   n ".., 59) ........................................................... = 59
write(2, "" ", 1) ............................................................................................ = 1
write(2, "\n", 1) ............................................................................................ = 1
write(2, "D e t a i l :   ", 8) .............................................................................. = 8
write(2, "[ n o   d e t a i l ] ", 11) ....................................................................... = 11
write(2, "\n", 1) ............................................................................................ = 1
shutdown(4, SHUT_RDWR) ....................................................................................... = 0
close(4) ..................................................................................................... = 0
exit(0) ...................................................................................................... WIFEXITED(0)

>int err = service.serve();

I assume serve() is dispatching to your calcService member functions?

--> Yes this is correct

extern "C" {

#include "apache_gsoap.h"

}

Since apache_gsoap.h has already been C++ified, you shouldn't put it in another extern "C" block.

-->Yes this is correct but using extern "C" multiple times should not make any difference ?

Please help what else we can try.

Thanks,

Biswadeep.

Dennis Handly · ‎07-25-2014

-->The source is in pure "C" ( not in C++) when we are using C compiler.

But calculator.cpp is C++. Or is that different than calc.so?

>we can not use tusc on a shared library

Yes, you use tusc on processes.

write(1, "a f t e r c a l l t o A d ".., 18)

It seems to go wrong here. Is this your message? You may have to ask tusc to print longer strings in the writes.

write(1, "S O A P E R R O R : ", 11)
write(1, "R e s u l t 2 : ", 8)
write(1, "0 ", 1)

-->using extern "C" multiple times should not make any difference?

It has caused compilation errors in the past and not a good idea to do.

Biswadeep · ‎07-28-2014

--->But calculator.cpp is C++. Or is that different than calc.so?

We are trying to build our webservice in two differnet language: i.e in C and C++ respectively.

The codes are in C and C++ respectively and the compiler is different for both the cases and the calc.so are also different in both the cases.

Both the webservices are distinct.

Our webservice is working fine with C code but in C++ we are facing issues as mentioned above.

Hope now its clear.Sorry for the confusion.

--->Yes, you use tusc on processes.

We tried running our code using the following command:

tusc -f -o calc.tusc -p 19174( 19174 is the main process id,after loading our calc.so(in C++) , mod_gsoap.so(in C) into the apache server and starting it)

tail -f calc.tusc

Here is our output file

[19174] select(0, NULL, NULL, NULL, 0x87ffffffffff65d0) ...................................................... [sleeping]

[19174] select(0, NULL, NULL, NULL, 0x87ffffffffff65d0) ...................................................... = 0

[19174] waitpid(-1, WIFEXITED(0), WNOHANG|WUNTRACED) ......................................................... = 0