I figured out. I compiled the code in the different shell, which does not know package config path. The code was compiled okay after adding the "PKG_CONFIG_PATH=/usr/local/lib/pkgconfig" However, the executable does not work, even though the code is exactly the same as example code, appsink-src.c. The example, which is under the plug-in source tree, was compiled ok and worked perfectly. Why the code I compiled did not work? Do I have to add more linker options? My makefile looks like below: CC=g++ GST_LIBS=`pkg-config --libs gstreamer-0.10 gstreamer-app-0.10` GST_CFLAGS= `pkg-config --cflags gstreamer-0.10 gstreamer-app-0.10` CFLAGS=-Wall -g BINS=appsinktest OBJS=main.o all: $(BINS) main.o: main.cc $(CC) $(CFLAGS) $(GST_CFLAGS) $(GST_LIBS) -c main.cc appsinktest: $(OBJS) $(CC) $(CFLAGS) $(GST_CFLAGS) $(GST_LIBS) $+ -o $(BINS) clean: rm -rf $(OBJS) rm -rf $(BINS) <div class="gmail_quote"> On Tue, Jul 21, 2009 at 12:04 PM, joh <<a href="mailto:joh.vlcdev@gmail.com">joh.vlcdev@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> HI! I was using gstreamer standard distributions from fedora repository, but needed to update them from source code to use latest version of appsrc/sink . My problem is when I link the application against libgstapp with the option of -lgstapp-0.10, I got some link errors. It seems like I am linking to old version of gst-plugins-base library. Error messages are as follows: ( oops! almost forgot to mentiion this. the code in main.cc is copy of exmplae code "appsink-src.c"); --------------------------------------------------------------------------------------------------- g++ -Wall -g `pkg-config --cflags gstreamer-0.10` `pkg-config --libs gstreamer-0.10` -lgstapp-0.10 -lgstinterfaces-0.10 -c main.cc g++ -Wall -g `pkg-config --cflags gstreamer-0.10` `pkg-config --libs gstreamer-0.10` -lgstapp-0.10 -lgstinterfaces-0.10 main.o -o appsinktest /usr/local/lib/libgstbase-0.10.so.0: undefined reference to `gst_util_seqnum_next' /usr/local/lib/libgstbase-0.10.so.0: undefined reference to `gst_message_set_seqnum' /usr/local/lib/libgstbase-0.10.so.0: undefined reference to `gst_event_set_seqnum' /usr/local/lib/libgstbase-0.10.so.0: undefined reference to `gst_event_get_seqnum' collect2: ld returned 1 exit status make: *** [appsinktest] Error 1 --------------------------------------------------------------------------------------------------- Is there any specific way to install the gstreamer package from source code? The package I installed from source: 1. gstreamer-0.10.23 2. gst-plugins-base-0.10.23 3. gst-plugins-good-0.10.15 4. gst-plugins-bad-0.10.13 5. gst-plugins-ugly-0.10.12 6. gst-ffmpeg-0.10.8 Once I did "export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig" What I did for every source package: 1. "./configure" 2. "make" 3. "sudo make install" Everything was okay. Am I missing something? Thank you in advance! Justin </blockquote></div>