How to add libmraa to compile process

[ThomasM]

Hi there,

I’m currently working on an Intel Edison and try to get the libmraa library working (https://iotdk.intel.com/docs/master/mraa/). If I compile the demo source with vi on the edison everything works (for my bash commands sroll down) and the build does not fail.

If I try to use VisualGDB within the VisualStudio environment the build fails. The compiler tells me that the functions provided by the library  libmraa are not found.

1>D:\HelloWorld\HelloWorld\HelloWorld\HelloWorld.cpp(12): error : undefined reference to `mraa_get_platform_name'
1>D:\HelloWorld\HelloWorld\HelloWorld\HelloWorld.cpp(13): error : undefined reference to `mraa_get_version'

My question is quite simple:
How can I compile the project with a libmraa library on a Win7 computer with VisualGDB?

Some more detailed information is coming up now. This is what I got on the edison:

Contents of Test.c
#include "mraa.h"
int main(int argc, char *argv[])
{    
    const char* board_name = mraa_get_platform_name();
    fprintf(stdout, "hello mraa\n Version: %s\n Running on %s\n", mraa_get_version(), board_name);
    return 0;
}

 

I compile on the edison with the following lines

$ gcc -o HelloDemo Test.c -lmraa
$ ./HelloDemo
hello mraa
 Version: v1.6.1
 Running on Intel Edison

Still on the edison

$ uname -a
Linux edison 3.10.17-poky-edison+ #1 SMP PREEMPT Fri Jun 19 12:06:40 CEST 2015 i686 GNU/Linux
$ opkg list | grep mraa
mraa - 0.9.0 - mraa built using CMake
mraa - 1.6.1 - mraa built using CMake
mraa - 0.7.5.60
mraa-dbg - 0.7.5-r0
mraa-dev - 0.7.5-r0
mraa-doc - 0.7.5-r0

Here are my settings on VisualGDB:

The ../../../Bibliotheken/MRAA is the directory identical to the github page from https://github.com/intel-iot-devkit/mraa and contains nothing but *.h files.

Thanks for all the help!

• This topic was modified 7 years, 7 months ago by ThomasM. Reason: Fixed typos

[support]

Hi,

Normally it should be as easy as adding “mraa” to the “Library names” field.

If you get a “cannot find -lmraa” error, please try the following command line on your Edison:

gcc -o HelloDemo Test.c -lmraa -Wl,-verbose

Then check the verbose link log for the actual path of libmraa.a. Once you locate it, simply copy it in the corresponding directory inside your toolchain’s sysroot and VisualGDB should be able to link your program with it.

[ThomasM]

Hey,

thanks for the answer. I tried the command on the Edison itself. This is a part of the gcc output

attempt to open /usr/lib/gcc/i586-poky-linux/4.9.1/libmraa.so failed
attempt to open /usr/lib/gcc/i586-poky-linux/4.9.1/libmraa.a failed
attempt to open /usr/lib/gcc/i586-poky-linux/4.9.1/../../../i586-poky-linux/4.9.1/libmraa.so failed
attempt to open /usr/lib/gcc/i586-poky-linux/4.9.1/../../../i586-poky-linux/4.9.1/libmraa.a failed
attempt to open /usr/lib/gcc/i586-poky-linux/4.9.1/../../../libmraa.so succeeded

I ran another command to make sure the libmraa.a is installed

/usr/lib$ ls | grep mraa
libmraa.so
libmraa.so.0
libmraa.so.1
libmraa.so.1.6.1
libmraajava.so

It seems like I don’t have the libmraa.a installed. Is there an easy way to do so? Everything that I tried was just for dynamic linking.

Greetings,
Thomas

[ThomasM]

Nevermind. It seems like the build is happy with the libmraa.so as well 😉

[support]

Hi,

No problem. The shared library should do as well, as long as it is always present on your target system.

[Author]

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