I have a CPP project, and i need to use some bluez's API(According to the example bluez/tools/btgatt-server.c). In the Makefile.tools I found that:
tools_btgatt_server_SOURCES = tools/btgatt-server.c src/uuid-helper.c
tools_btgatt_server_LDADD = src/libshared-mainloop.la \
lib/libbluetooth-internal.la
So, if I want to use those API i need the three files uuid-helper.c libshared-mainloop.la libbluetooth-internal.la. I know .la file is only a text file, but i don't know how to "add/use" them to my project makefile. In other words, i want to know how to use the existing .la files in my project(a simple Makefile example will be great). Or is there any other way to call bluez's API?
Any advise would be appreciated.
Related
Can anyone explain to me how to use ReaderWriterOBJ in OpenSceneGraph? I want to load an obj file along with the mtl file. I have already built the solution for readerWriterObj code and created a dll file.
The ReaderWriter's are just file loaders. You have to use them in context of an application, like osgviewer, one of the examples included in OSG. If you've gone through the process of building OSG, you might have already built osgviewer, which will use the appropriate DLL's to load files.
eg
osgviewer FILE.obj
will open FILE.obj, with its associated material file[s].
I am writing an extension for the Scratch text editor application on Elementary OS Luna. But the documentation is practically non-existent for extension creation and I have no idea how to proceed after writing my main code for the extension.
I've already written the extension. I cannot use or test it yet as it needs to be "installed". I spent hours looking for docs but they do not exist. I did however, find a comment on the scratch launchpad page that says
Generally you have to generate a pluginname.so file and put it in
lib/scratch/plugins/pluginname with a pluginname.plugin file
Great. This seems like the last part of creating an extension for Scratch. What is a .so file, and how do I generate one? I've already created the other necessary files like the .plugin file and the .vala file.
Yes, I have searched for .so files but all I found were random things about it like using it with C, or C++ headers but obviously that won't work for me, since I'm using Vala?
How do I generate a .so file? What do I generate it from?
I think the The Vala tutorial could be helpful on creating the actual Shared library or Shared Object.
You can use the autotools, cmake or you can compile and link a shared library directly from the command line, quoted from the Vala tutorial:
Compilation and linking using Command Line
Vala is not yet capable of directly creating dynamic or static
libraries. To create a library, proceed with the -c (compile only)
switch and link the object files with your favourite linker, i.e.
libtool or ar.
$ valac -c ...(source files)
$ ar cx ...(object files)
or by compiling the intermediate C code with gcc
$ valac -C ...(source files)
$ gcc -o my-best-library.so --shared -fPIC ...(compiled C code files)...
From the Scratch Wiki
Due to browser security restrictions, Scratch 2.0 cannot interact with
hardware devices directly. Instead, hardware extensions come with a
helper app, a separate application that the user must install and run
on their computer. Scratch communicates with the helper app via HTTP
requests, and the helper app talks to the hardware. In the future,
some extensions may package their helper apps as browser plugins.
Here are the steps for creating and testing a Scratch extension:
Create an extension description file
Create your helper app and start it
Open the Scratch 2 Offline Editor
Import the extension description (shift-click on "File" and select "Import Experimental Extension" from the menu)
The new extension blocks will appear in the More Blocks palette
Test your extension and iterate!
Helper apps can be written in any language that supports server sockets, such as Python, Node.js, Java, C, etc.
Like you I've chased around the wiki but I cannot find an example with source. So all I can do is to address your question generally.
If you look at Build .so file from .c file using gcc command line you'll see how a simple .so can be created. However what code goes into a Scratch extension I don't know. Sorry.
Edit: More googling and I've found a sample from Nathan Dinsmore on GitHub that doesn't use C rather it uses JavaScript, and though it doesn't create a .so extension, it does have what appears to be a full description of creating an extension. He also provides a couple of tutorials.
Edit++ : And here is another sample written in Java.
I am trying to learn CMake. I have the Mastering CMake book and I'm trying to go through my first "easy" tutorial. Using CMake: Hello World Example
I made it through the first part alright, but when I tried to add the sub folders for the "Building a library" part of the tutorial I'm just not getting it. I followed the instructions all the way to the very end.
**We've seen an example of how to build a program. Now let's make a library as well. The library will be called "namer" and it will have a single function "getWorld" that returns the name of the nearest planet. We choose to put this library in a subdirectory called "namer" - it doesn't really matter where we put it, this is just an example.
I made it a subfolder in my HelloWorld project. Should I be making this a separate project?
**One way we can help CMake find the Namer package (which will be our namer library) is by writing a helper script called FindNamer.cmake. This is just another file written in the CMake language that pokes around in all the places our library might be hiding. Here is an example (put this in "hello/FindNamer.cmake"):
This is my FindNamer.cmake file:
find_path(Namer_INCLUDE_DIRS world.h /usr/include "$ENV{NAMER_ROOT}")
find_library(Namer_LIBRARIES namer /usr/lib "$ENV{NAMER_ROOT}")
set(Namer_FOUND TRUE)
if (NOT Namer_INCLUDE_DIRS)
set(Namer_FOUND FALSE)
endif (NOT Namer_INCLUDE_DIRS)
if (NOT Namer_LIBRARIES)
set(Namer_FOUND FALSE)
endif (NOT Namer_LIBRARIES)
**The important parts here are the "find_path" and "find_library" commands, which look for the header file world.h and the namer library.
I followed the next instructions and at the very end the tutorial includes this:
**If we try again, configuration will still fail since the search path we gave for "find_path" and "find_library" doesn't actually include the needed files. We could copy them, or have added a hard-coded directory to find_path and find_library pointing to where the files are on our hard drive - but better, in the CMake GUI on windows or by running "ccmake ." on Linux, we can just fill in the directories there.
At this point I am completely confused (Newbie!!!!). I don't have a NamerConfig.cmake or namer-config.cmake file and I don't know what the find_path and find_library is supposed to be pointing to.
Thank you in advance for your help,
Severely Confused :-(
I said I was a newbie. I guess I'm a little tired too! Yes, these must be in two separate projects.
I'm trying to create a shared library for Linux such that:
other programs can use its functions and its objects
the code is not visible to final user
What i did is create a shared library with Eclipse. This library uses pthreads.
I generated .so and .lib. The .lib is in LIBRARY/Lib while the .so is in LIBRARY/Release.
Then i created another project which should use this library and i gave the path of the .lib file and the path of the .h file which only contains the inclusions of all the necessary .h of the library.
All seems working but when i run the program it crashes. When debugging it I receive the following message:
Can't find a source file at "pthread_mutex_lock.c"
Locate the file or edit the source lookup path to include its location.
What's wrong? Can someone help me please?
EDIT: I changed nothing and now I have a different error, some lines before the previous:
Can't find a source file at "random.c"
Locate the file or edit the source lookup path to include its location.
other programs can use its functions and its objects
the code is not visible to final user
These two goals directly contradict each other, and achieving both at the same time is impossible on Linux.
If some program can use your library, then I can write a new program that can do so as well.
In this instance I'm using c with autoconf, but the question applies elsewhere.
I have a glade xml file that is needed at runtime, and I have to tell the application where it is. I'm using autoconf to define a variable in my code that points to the "specified prefix directory"/app-name/glade. But that only begins to work once the application is installed. What if I want to run the program before that point? Is there a standard way to determine what paths should be checked for application data?
Thanks
Thanks for the responses. To clarify, I don't need to know where the app data is installed (eg by searching in /usr,usr/local,etc etc), the configure script does that. The problem was more determining whether the app has been installed yet. I guess I'll just check in install location first, and if not then in "./src/foo.glade".
I dont think there's any standard way on how to locate such data.
I'd personally do it in a way that i'd have a list of paths and i'd locate if i can find the file from anyone of those and the list should containt the DATADIR+APPNAME defined from autoconf and CURRENTDIRECTORY+POSSIBLE_PREFIX where prefix might be some folder from your build root.
But in any case, dont forget to use those defines from autoconf for your data files, those make your software easier to package (like deb/rpm)
There is no prescription how this should be done in general, but Debian packagers usually installs the application data somewhere in /usr/share, /usr/lib, et cetera. They may also patch the software to make it read from appropriate locations. You can see the Debian policy for more information.
I can however say a few words how I do it. First, I don't expect to find the file in a single directory; I first create a list of directories that I iterate through in my wrapper around fopen(). This is the order in which I believe the file reading should be done:
current directory (obviously)
~/.program-name
$(datadir)/program-name
$(datadir) is a variable you can use in Makefile.am. Example:
AM_CPPFLAGS = $(ASSERT_FLAGS) $(DEBUG_FLAGS) $(SDLGFX_FLAGS) $(OPENGL_FLAGS) -DDESTDIRS=\"$(prefix):$(datadir)/:$(datadir)/program-name/\"
This of course depends on your output from configure and how your configure.ac looks like.
So, just make a wrapper that will iterate through the locations and get the data from those dirs. Something like a PATH variable, except you implement the iteration.
After writing this post, I noticed I need to clean up our implementation in this project, but it can serve as a nice start. Take a look at our Makefile.am for using $(datadir) and our util.cpp and util.h for a simple wrapper (yatc_fopen()). We also have yatc_find_file() in case some third-party library is doing the fopen()ing, such as SDL_image or libxml2.
If the program is installed globally:
/usr/share/app-name/glade.xml
If you want the program to work without being installed (i.e. just extract a tarball), put it in the program's directory.
I don't think there is a standard way of placing files. I build it into the program, and I don't limit it to one location.
It depends on how much customising of the config file is going to be required.
I start by constructing a list of default directories and work through them until I find an instance of glade.xml and stop looking, or not find it and exit with an error. Good candidates for the default list are /etc, /usr/share/app-name, /usr/local/etc.
If the file is designed to be customizable, before I look through the default directories, I have a list of user files and paths and work through them. If it doesn't find one of the user versions, then I look in the list of default directories. Good candidates for the user config files are ~/.glade.xml or ~/.app-name/glade.xml or ~/.app-name/.glade.xml.