[libvirt] Compiling C++ program with libvirt

[Matthias Bolte]

2010/7/22 adrian wyssen <wyssenadrian at gmail.com>:
> Hi everyone
> I am trying to compile a C++ program which uses libvirt to connect to an
> ESXi host. I got the code running if I wrote it in C, directly in the
> hellolibvirt.c example. However, I am now trying to compile that code in a
> C++ file which is not inside the example directory.
> I tried to compile with the following command:
> g++ -g -D debug=1 -c -llibvirt ESXWrapper.cpp
> g++ -g -D debug=1 -o ESXWrapper ESXWrapper.o
> The first line passes and creates ESXWrapper.o file. But when I run the
> second line, it gives me the following error:
> ---
> g++ -g -D debug=1 -c -llibvirt ESXWrapper.cpp

At this point g++ (actually ld) should have told you that it cannot
find liblibvirt.so. when you pass a library to g++ using the -l you
need to remove the lib prefix from the name, because it's implicit and
ld will add it on its own. Passing -llibvirt will make ld look for the
wrong file.

> g++ -g -D debug=1 -o ESXWrapper ESXWrapper.o
> ESXWrapper.o: In function `VPopCWrapper':
> /home/wyssen/school/Dropbox/virtualPOPC-1/NEW/vpopcwrapper/ESXWrapper.cpp:124:
> undefined reference to `virConnectOpenAuth'
> /home/wyssen/school/Dropbox/virtualPOPC-1/NEW/vpopcwrapper/ESXWrapper.cpp:133:
> undefined reference to `virConnectGetURI'
> /home/wyssen/school/Dropbox/virtualPOPC-1/NEW/vpopcwrapper/ESXWrapper.cpp:144:
> undefined reference to `virConnectClose'
> /home/wyssen/school/Dropbox/virtualPOPC-1/NEW/vpopcwrapper/ESXWrapper.cpp:124:
> undefined reference to `virConnectOpenAuth'
> /home/wyssen/school/Dropbox/virtualPOPC-1/NEW/vpopcwrapper/ESXWrapper.cpp:133:
> undefined reference to `virConnectGetURI'
> /home/wyssen/school/Dropbox/virtualPOPC-1/NEW/vpopcwrapper/ESXWrapper.cpp:144:
> undefined reference to `virConnectClose'
> ESXWrapper.o: In function `showError':
> /home/wyssen/school/Dropbox/virtualPOPC-1/NEW/vpopcwrapper/ESXWrapper.cpp:186:
> undefined reference to `virConnCopyLastError'
> /home/wyssen/school/Dropbox/virtualPOPC-1/NEW/vpopcwrapper/ESXWrapper.cpp:202:
> undefined reference to `virResetError'
> collect2: ld returned 1 exit status
> make: *** [all] Error 1
> ---
> My makefile is the follwing:
> ---
> #vars
> CC=g++
> OUTPUTFILE=ESXWrapper
> O_FILES=ESXWrapper.o
> FLAGS=-g -D debug=1
>
> .PHONY: all
> all: esxwrapper
> $(CC) $(FLAGS) -o $(OUTPUTFILE) $(O_FILES)
> esxwrapper: ESXWrapper.cpp VPopCWrapper.h
> $(CC) $(FLAGS) -c -llibvirt ESXWrapper.cpp

$(CC) $(FLAGS) -c -lvirt ESXWrapper.cpp

This should work better, assuming libvirt.so can be found in the
common ld library path.

>
> .PHONY: run
> run: all
> ./bignum
>
> .PHONY: clean
> clean:
> rm -f $(O_FILES)
> .PHONY: clean_all
> clean_all: clean
> rm -f $(OUTPUTFILE)
> ---
> Can anybody give me a hint, how to link correctly to libvirt. And also tell
> me, if there are special functions to use with C++, other than the examples
> provided in the source code, which are written in C.
> Thank you
> Adrian

Just use the C API, nothing special for C++.

Matthias