How do I build simple application that uses libiio?

1. PetaLinux itself is based off Yocto Linux, which itself uses a layering process to construct a custom image with integrated libraries. So if you want a new library, it should be built into a Yocto/Peta layer. ADI provides a common layer set which does have libiio support: https://github.com/analogdevicesinc/meta-adi/tree/master/meta-adi-xilinx

2. Once you have a built PetaLinux image with libiio built into it, you can cross-compile against its sysroot to build applications for that architecture and library set. The sysroot should be a artifact generated from the build process. However, you will likely need to ask Xilinx where it gets placed.

I will also mention an alternative. If you leverage Kuiper Linux (the ADI Linux distribution for Zynq+Intel+RPI) it comes with libiio installed and compilers. Therefore, you can just build on the system itself: https://www.analog.com/en/design-center/evaluation-hardware-and-software/software/kuiper-linux.html

-Travis

Thanks for your quick reply Travis, 

I tried 1+2 but I failed in the cross-compile stage.

Regarding 3 - Sounds interesting, I want to try this, but as I understand - Kuiper Linux and Petalinux (the linux image that is built using petalinux build system) are different, right ? 

To explain my question - I want to build a new custom BOOT.bin file (which is based on a custom system.bit file that I generate from Vivado) and deploy it to Zynq - if I build the BOOT.bin using Petalinux build system - will it run with Kuiper Linux without any problem? 

So PetaLinux is really independent of the bitstream creation. So generally yes you can use the generated bitstreams with Kuiper. This typically will require packaging the bistream into a BOOT.BIN. Here is the process: https://wiki.analog.com/resources/tools-software/linux-software/build-the-zynq-boot-image

-Travis

Travis, thanks again for your help, I finally managed to build an application that uses the libiio library and run it on the Zynq processor , I'm writing the steps here so everyone else, who might face the challenges I met, can use and solve them: 

1. I have one SD card that was flashed with your pure Kuiper Linux image.
2. I have other SD card with Petalinux image that I built using the Petalinux build system (I use it to build and package custom FPGA bit streams that I create and compile custom Device Tree files [I need to make changes to both bit stream and device tree]) .


I use the SD from 2 in production.
When I want to build libiio application I use the SD from 1 and run the following in order to compile the application: 

gcc my_app.c -o my_app -I/usr/include/ -L/usr/local/src/libiio/build/ -liio

I had to use -I (capital i) to indicate the path where iio.h file is located, -L to indicate where the libiio.so file is located and -liio to tell the compiler to link with libiio. 


When my_app file was created I copied it to the SD card from 2 and run it there.

So bottom line is - I still have the power of Petalinux for building and packaging the image (no need to setup a new environment from scratch for Kuiper), and I use the Kuiper image for "cross-compiling" the application.