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Difference between revisions of "Mraa"

 
(5 intermediate revisions by the same user not shown)
Line 142: Line 142:
  
 
<pre>
 
<pre>
−
root@rockpin10bc:/home/rock# apt-get install -y git build-essential swig3.0 python-dev python3-dev libnodejs-dev  cmake libjson-c-dev
+
root@rockpin10bc:/home/rock# apt-get install -y git build-essential swig3.0 python-dev python3-dev libnode-dev  cmake libjson-c-dev
 
root@rockpin10bc:/home/rock# apt-get install -y libc6 libgcc1 libstdc++6 python python2.7 libpython2.7 python3.8 libpython3.8 python3-dev python3
 
root@rockpin10bc:/home/rock# apt-get install -y libc6 libgcc1 libstdc++6 python python2.7 libpython2.7 python3.8 libpython3.8 python3-dev python3
 
root@rockpin10bc:/home/rock# apt-get install -y libgtest-dev pkg-config cmake-data
 
root@rockpin10bc:/home/rock# apt-get install -y libgtest-dev pkg-config cmake-data
Line 188: Line 188:
 
root@rockpin10bc:/home/rock/mraa/build# mraa-gpio version
 
root@rockpin10bc:/home/rock/mraa/build# mraa-gpio version
 
Version v2.1.0-11-g06b2be2 on ROCK Pi 4
 
Version v2.1.0-11-g06b2be2 on ROCK Pi 4
 +
</pre>
 +
 +
 +
==== Install example: Install Mraa on ROCK Pi 4C Debian Bullseye system ====
 +
 +
 +
Configure the linux java environment
 +
<pre>
 +
Download jdk for linux arm64 version, for example, openjdk-18.0.2.1_linux-aarch64
 +
root@rock-4c-plus:/home/rock# cd /usr/local
 +
root@rock-4c-plus:/home/rock# mkdir java
 +
root@rock-4c-plus:/home/rock# cd java
 +
root@rock-4c-plus:/home/rock# tar xzvf openjdk-18.0.2.1_linux-aarch64_bin.tar.gz
 +
root@rock-4c-plus:/home/rock# ls
 +
jdk-18.0.2.1  openjdk-18.0.2.1_linux-aarch64_bin.tar.gz
 +
root@rock-4c-plus:/home/rock# mv  jdk-18.0.2.1  jdk18
 +
 +
# modify /etc/profile
 +
root@rock-4c-plus:/usr/local/java# cat /etc/profile
 +
# /etc/profile: system-wide .profile file for the Bourne shell (sh(1))
 +
# and Bourne compatible shells (bash(1), ksh(1), ash(1), ...).
 +
 +
if [ "$(id -u)" -eq 0 ]; then
 +
  PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
 +
else
 +
  PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games"
 +
fi
 +
export PATH
 +
 +
if [ "${PS1-}" ]; then
 +
  if [ "${BASH-}" ] && [ "$BASH" != "/bin/sh" ]; then
 +
    # The file bash.bashrc already sets the default PS1.
 +
    # PS1='\h:\w\$ '
 +
    if [ -f /etc/bash.bashrc ]; then
 +
      . /etc/bash.bashrc
 +
    fi
 +
  else
 +
    if [ "$(id -u)" -eq 0 ]; then
 +
      PS1='# '
 +
    else
 +
      PS1='$ '
 +
    fi
 +
  fi
 +
fi
 +
 +
if [ -d /etc/profile.d ]; then
 +
  for i in /etc/profile.d/*.sh; do
 +
    if [ -r $i ]; then
 +
      . $i
 +
    fi
 +
  done
 +
  unset i
 +
fi
 +
 +
 +
export JAVA_HOME=/usr/local/java/jdk18
 +
export JRE_HOME=${JAVA_HOME}/jre
 +
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
 +
export PATH=${JAVA_HOME}/bin:$PATH
 +
 +
# Bring into effect
 +
root@rock-4c-plus:/usr/local/java# source /etc/profile
 +
 +
# verification
 +
root@rock-4c-plus:/usr/local/java# java -version
 +
openjdk version "18.0.2.1" 2022-08-18
 +
OpenJDK Runtime Environment (build 18.0.2.1+1-1)
 +
OpenJDK 64-Bit Server VM (build 18.0.2.1+1-1, mixed mode, sharing)
 +
 +
root@rock-4c-plus:/usr/local/java# javac -version
 +
javac 18.0.2.1
 +
 +
</pre>
 +
 +
For Debian Bullseye Distribution the below commands install the essential set:
 +
<pre>
 +
root@rock-4c-plus:/home/rock# apt-get install -y git build-essential swig python-dev python3-dev libnode-dev  cmake libjson-c-dev
 +
root@rock-4c-plus:/home/rock# apt-get install -y libc6 libgcc1 libstdc++6 python python2.7 libpython2.7 python3.8 libpython3.8 python3-dev python3
 +
root@rock-4c-plus:/home/rock# apt-get install -y libgtest-dev pkg-config cmake-data
 +
</pre>
 +
Get source code.
 +
<pre>
 +
root@rock-4c-plus:/home/rock# git clone -b master https://github.com/radxa/mraa.git
 +
root@rock-4c-plus:/home/rock# cd mraa
 +
</pre>
 +
 +
Patch the source code for building mraa with Python and java
 +
<pre>
 +
diff --git a/CMakeLists.txt b/CMakeLists.txt
 +
index 250d910..6446f11 100644
 +
--- a/CMakeLists.txt
 +
+++ b/CMakeLists.txt
 +
@@ -1,4 +1,4 @@
 +
-cmake_minimum_required (VERSION 2.8.11)
 +
+cmake_minimum_required (VERSION 3.13.0)
 +
project (mraa C CXX)
 +
 +
FIND_PACKAGE (Threads REQUIRED)
 +
@@ -9,6 +9,8 @@ if (CMAKE_VERSION VERSION_LESS "3.1")
 +
  endif ()
 +
else ()
 +
  set (CMAKE_C_STANDARD 99)
 +
+  cmake_policy(SET CMP0078 OLD)
 +
+  cmake_policy(SET CMP0086 NEW)
 +
endif ()
 +
 +
###############################################################################
 +
@@ -145,8 +147,8 @@ include_directories (${SYSTEM_USR_DIR})
 +
option (BUILDDOC "Build all doc." OFF)
 +
option (BUILDSWIG "Build swig modules." ON)
 +
option (BUILDSWIGPYTHON "Build swig python modules." ON)
 +
-option (BUILDSWIGNODE "Build swig node modules." ON)
 +
-option (BUILDSWIGJAVA "Build Java API." OFF)
 +
+option (BUILDSWIGNODE "Build swig node modules." OFF)
 +
+option (BUILDSWIGJAVA "Build Java API." ON)
 +
option (USBPLAT "Detection USB platform." OFF)
 +
option (FIRMATA "Add Firmata support to mraa." OFF)
 +
option (ONEWIRE "Add Onewire support to mraa." ON)
 +
 +
 +
diff --git a/include/version.h b/include/version.h
 +
index 47366ef..3a567a1 100644
 +
--- a/include/version.h
 +
+++ b/include/version.h
 +
@@ -11,8 +11,8 @@
 +
extern "C" {
 +
#endif
 +
 +
-const char* gVERSION;
 +
-const char* gVERSION_SHORT;
 +
+extern const char* gVERSION;
 +
+extern const char* gVERSION_SHORT;
 +
 +
#ifdef __cplusplus
 +
}
 +
 +
</pre>
 +
 +
Build and install mraa.
 +
 +
<pre>
 +
root@rock-4c-plus:/home/rock# mkdir build
 +
root@rock-4c-plus:/home/rock# cd build/
 +
root@rock-4c-plus:/home/rock# cmake ..
 +
root@rock-4c-plus:/home/rock# make
 +
rooroot@rock-4c-plus:/home/rock# make install
 +
root@rock-4c-plus:/home/rock# ldconfig
 +
root@rock-4c-plus:/home/rock# mraa-gpio version
 +
Version v2.1.0 on ROCK Pi 4
 
</pre>
 
</pre>
  
Line 209: Line 358:
  
 
<pre>
 
<pre>
−
root@rockpi-4b:/home/rock/mraa# git diff .
+
 
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
−
index 250d910..e418472 100644
+
index 250d910..9050100 100644
 
--- a/CMakeLists.txt
 
--- a/CMakeLists.txt
 
+++ b/CMakeLists.txt
 
+++ b/CMakeLists.txt
Line 220: Line 369:
 
   
 
   
 
  FIND_PACKAGE (Threads REQUIRED)
 
  FIND_PACKAGE (Threads REQUIRED)
 +
@@ -9,6 +9,8 @@ if (CMAKE_VERSION VERSION_LESS "3.1")
 +
  endif ()
 +
else ()
 +
  set (CMAKE_C_STANDARD 99)
 +
+  cmake_policy(SET CMP0078 OLD)
 +
+  cmake_policy(SET CMP0086 NEW)
 +
endif ()
 +
 +
###############################################################################
 
diff --git a/include/version.h b/include/version.h
 
diff --git a/include/version.h b/include/version.h
 
index 47366ef..3a567a1 100644
 
index 47366ef..3a567a1 100644

Latest revision as of 02:20, 12 June 2023

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Mraa on ROCK Pi boards

This document describes how to build and use mraa for ROCK Pi boards.

List of ROCK Pi Boards supported

  • ROCK Pi 4 A/B/C
  • ROCK Pi E
  • ROCK Pi N10
  • ROCK Pi S
  • ROCK Pi X

List of Linux Distributions

  • Ubuntu
  • Debian
  • Yocto (mraa-radxa_git.bb)

Install example: Install Mraa on ROCK Pi N10 Debian system

For Debian Distribution the below commands install the essential set: 

root@rockpin10bc:/home/rock# apt-get install -y git build-essential swig3.0 python-dev  cmake libjson-c-dev libnode-dev
root@rockpin10bc:/home/rock# apt-get install -y libc6 libjson-c3 libgcc1 libstdc++6 python2.7 libpython2.7 python3.7 libpython3.7 python3-dev
root@rockpin10bc:/home/rock# apt-get install -y libgtest-dev pkg-config cmake-data

Get source code. 

root@rockpin10bc:/home/rock# git clone -b master https://github.com/radxa/mraa.git
root@rockpin10bc:/home/rock# cd mraa

Patch the source code for building mraa with Python. 

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 250d910..f1880e1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -145,7 +145,7 @@ include_directories (${SYSTEM_USR_DIR})
 option (BUILDDOC "Build all doc." OFF)
 option (BUILDSWIG "Build swig modules." ON)
 option (BUILDSWIGPYTHON "Build swig python modules." ON)
-option (BUILDSWIGNODE "Build swig node modules." ON)
+option (BUILDSWIGNODE "Build swig node modules." OFF)
 option (BUILDSWIGJAVA "Build Java API." OFF)
 option (USBPLAT "Detection USB platform." OFF)
 option (FIRMATA "Add Firmata support to mraa." OFF)
@@ -156,7 +156,7 @@ option (FTDI4222 "Build with FTDI FT4222 subplatform support." OFF)
 option (ENABLEEXAMPLES "Disable building of examples" ON)
 option (INSTALLTOOLS "Install all tools" ON)
 option (BUILDTESTS "Override the addition of tests" ON)
-option (USEPYTHON3TESTS "Force tests to run with python3" OFF)
+option (USEPYTHON3TESTS "Force tests to run with python3" ON)
 
 set (BUILDARCH "" CACHE STRING "Override architecture to build for")

Build and install mraa. 

root@rockpin10bc:/home/rock/mraa# mkdir build
root@rockpin10bc:/home/rock/mraa# cd build/
root@rockpin10bc:/home/rock/mraa/build# cmake ..
root@rockpin10bc:/home/rock/mraa/build# make
root@rockpin10bc:/home/rock/mraa/build# make install
root@rockpin10bc:/home/rock/mraa/build# ldconfig
root@rockpin10bc:/home/rock/mraa/build# mraa-gpio version
Version v2.1.0-11-g06b2be2 on Radxa ROCK Pi N10

Install example: Install Mraa on CM3 IO Debian11 system

For Debian11 Distribution the below commands install the essential set: 

root@radxa-cm3-io:/home/rock# apt-get install -y git build-essential swig4.0 python-dev cmake libnode-dev python3-dev pkg-config

Get source code. 

root@radxa-cm3-io:/home/rock# git clone -b master https://github.com/radxa/mraa.git
root@radxa-cm3-io:/home/rock# cd mraa

Patch the source code for building mraa with Python. 

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 250d910..f1880e1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -145,7 +145,7 @@ include_directories (${SYSTEM_USR_DIR})
 option (BUILDDOC "Build all doc." OFF)
 option (BUILDSWIG "Build swig modules." ON)
 option (BUILDSWIGPYTHON "Build swig python modules." ON)
-option (BUILDSWIGNODE "Build swig node modules." ON)
+option (BUILDSWIGNODE "Build swig node modules." OFF)
 option (BUILDSWIGJAVA "Build Java API." OFF)
 option (USBPLAT "Detection USB platform." OFF)
 option (FIRMATA "Add Firmata support to mraa." OFF)
@@ -156,7 +156,7 @@ option (FTDI4222 "Build with FTDI FT4222 subplatform support." OFF)
 option (ENABLEEXAMPLES "Disable building of examples" ON)
 option (INSTALLTOOLS "Install all tools" ON)
 option (BUILDTESTS "Override the addition of tests" ON)
-option (USEPYTHON3TESTS "Force tests to run with python3" OFF)
+option (USEPYTHON3TESTS "Force tests to run with python3" ON)
 
 set (BUILDARCH "" CACHE STRING "Override architecture to build for")

Patch for later compilation with make 

diff --git a/include/version.h b/include/version.h
index 47366ef..3a567a1 100644
--- a/include/version.h
+++ b/include/version.h
@@ -11,8 +11,8 @@
 extern "C" {
 #endif
 
-const char* gVERSION;
-const char* gVERSION_SHORT;
+extern const char* gVERSION;
+extern const char* gVERSION_SHORT;
 
 #ifdef __cplusplus
 }

Build and install mraa. 

root@radxa-cm3-io:/home/rock/mraa# mkdir build
root@radxa-cm3-io:/home/rock/mraa# cd build/
root@radxa-cm3-io:/home/rock/mraa/build# cmake ..
root@radxa-cm3-io:/home/rock/mraa/build# make
root@radxa-cm3-io:/home/rock/mraa/build# make install
root@radxa-cm3-io:/home/rock/mraa/build# ldconfig
root@radxa-cm3-io:/home/rock/mraa/build# mraa-gpio version
Version v2.1.0-23-gfc8c906 on Radxa CM3 IO

Install example: Install Mraa on ROCK Pi 4C Ubuntu Focal system

For Ubuntu Distribution the below commands install the essential set: 

root@rockpin10bc:/home/rock# apt-get install -y git build-essential swig3.0 python-dev python3-dev libnode-dev  cmake libjson-c-dev
root@rockpin10bc:/home/rock# apt-get install -y libc6 libgcc1 libstdc++6 python python2.7 libpython2.7 python3.8 libpython3.8 python3-dev python3
root@rockpin10bc:/home/rock# apt-get install -y libgtest-dev pkg-config cmake-data

Get source code. 

root@rockpin10bc:/home/rock# git clone -b master https://github.com/radxa/mraa.git
root@rockpin10bc:/home/rock# cd mraa

Patch the source code for building mraa with Python. 

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 250d910..f1880e1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -145,7 +145,7 @@ include_directories (${SYSTEM_USR_DIR})
 option (BUILDDOC "Build all doc." OFF)
 option (BUILDSWIG "Build swig modules." ON)
 option (BUILDSWIGPYTHON "Build swig python modules." ON)
-option (BUILDSWIGNODE "Build swig node modules." ON)
+option (BUILDSWIGNODE "Build swig node modules." OFF)
 option (BUILDSWIGJAVA "Build Java API." OFF)
 option (USBPLAT "Detection USB platform." OFF)
 option (FIRMATA "Add Firmata support to mraa." OFF)
@@ -156,7 +156,7 @@ option (FTDI4222 "Build with FTDI FT4222 subplatform support." OFF)
 option (ENABLEEXAMPLES "Disable building of examples" ON)
 option (INSTALLTOOLS "Install all tools" ON)
 option (BUILDTESTS "Override the addition of tests" ON)
-option (USEPYTHON3TESTS "Force tests to run with python3" OFF)
+option (USEPYTHON3TESTS "Force tests to run with python3" ON)
 
 set (BUILDARCH "" CACHE STRING "Override architecture to build for")

Build and install mraa. 

root@rockpin10bc:/home/rock/mraa# mkdir build
root@rockpin10bc:/home/rock/mraa# cd build/
root@rockpin10bc:/home/rock/mraa/build# cmake ..
root@rockpin10bc:/home/rock/mraa/build# make
root@rockpin10bc:/home/rock/mraa/build# make install
root@rockpin10bc:/home/rock/mraa/build# ldconfig
root@rockpin10bc:/home/rock/mraa/build# mraa-gpio version
Version v2.1.0-11-g06b2be2 on ROCK Pi 4


Install example: Install Mraa on ROCK Pi 4C Debian Bullseye system

Configure the linux java environment 

Download jdk for linux arm64 version, for example, openjdk-18.0.2.1_linux-aarch64
root@rock-4c-plus:/home/rock# cd /usr/local
root@rock-4c-plus:/home/rock# mkdir java
root@rock-4c-plus:/home/rock# cd java
root@rock-4c-plus:/home/rock# tar xzvf openjdk-18.0.2.1_linux-aarch64_bin.tar.gz
root@rock-4c-plus:/home/rock# ls 
jdk-18.0.2.1  openjdk-18.0.2.1_linux-aarch64_bin.tar.gz
root@rock-4c-plus:/home/rock# mv  jdk-18.0.2.1  jdk18

# modify /etc/profile
root@rock-4c-plus:/usr/local/java# cat /etc/profile
# /etc/profile: system-wide .profile file for the Bourne shell (sh(1))
# and Bourne compatible shells (bash(1), ksh(1), ash(1), ...).

if [ "$(id -u)" -eq 0 ]; then
  PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
else
  PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games"
fi
export PATH

if [ "${PS1-}" ]; then
  if [ "${BASH-}" ] && [ "$BASH" != "/bin/sh" ]; then
    # The file bash.bashrc already sets the default PS1.
    # PS1='\h:\w\$ '
    if [ -f /etc/bash.bashrc ]; then
      . /etc/bash.bashrc
    fi
  else
    if [ "$(id -u)" -eq 0 ]; then
      PS1='# '
    else
      PS1='$ '
    fi
  fi
fi

if [ -d /etc/profile.d ]; then
  for i in /etc/profile.d/*.sh; do
    if [ -r $i ]; then
      . $i
    fi
  done
  unset i
fi


export JAVA_HOME=/usr/local/java/jdk18
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH

# Bring into effect
root@rock-4c-plus:/usr/local/java# source /etc/profile

# verification
root@rock-4c-plus:/usr/local/java# java -version
openjdk version "18.0.2.1" 2022-08-18
OpenJDK Runtime Environment (build 18.0.2.1+1-1)
OpenJDK 64-Bit Server VM (build 18.0.2.1+1-1, mixed mode, sharing)

root@rock-4c-plus:/usr/local/java# javac -version
javac 18.0.2.1

For Debian Bullseye Distribution the below commands install the essential set: 

root@rock-4c-plus:/home/rock# apt-get install -y git build-essential swig python-dev python3-dev libnode-dev  cmake libjson-c-dev
root@rock-4c-plus:/home/rock# apt-get install -y libc6 libgcc1 libstdc++6 python python2.7 libpython2.7 python3.8 libpython3.8 python3-dev python3
root@rock-4c-plus:/home/rock# apt-get install -y libgtest-dev pkg-config cmake-data

Get source code. 

root@rock-4c-plus:/home/rock# git clone -b master https://github.com/radxa/mraa.git
root@rock-4c-plus:/home/rock# cd mraa

Patch the source code for building mraa with Python and java 

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 250d910..6446f11 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required (VERSION 2.8.11)
+cmake_minimum_required (VERSION 3.13.0)
 project (mraa C CXX)
 
 FIND_PACKAGE (Threads REQUIRED)
@@ -9,6 +9,8 @@ if (CMAKE_VERSION VERSION_LESS "3.1")
   endif ()
 else ()
   set (CMAKE_C_STANDARD 99)
+  cmake_policy(SET CMP0078 OLD)
+  cmake_policy(SET CMP0086 NEW)
 endif ()
 
 ###############################################################################
@@ -145,8 +147,8 @@ include_directories (${SYSTEM_USR_DIR})
 option (BUILDDOC "Build all doc." OFF)
 option (BUILDSWIG "Build swig modules." ON)
 option (BUILDSWIGPYTHON "Build swig python modules." ON)
-option (BUILDSWIGNODE "Build swig node modules." ON)
-option (BUILDSWIGJAVA "Build Java API." OFF)
+option (BUILDSWIGNODE "Build swig node modules." OFF)
+option (BUILDSWIGJAVA "Build Java API." ON)
 option (USBPLAT "Detection USB platform." OFF)
 option (FIRMATA "Add Firmata support to mraa." OFF)
 option (ONEWIRE "Add Onewire support to mraa." ON)


diff --git a/include/version.h b/include/version.h
index 47366ef..3a567a1 100644
--- a/include/version.h
+++ b/include/version.h
@@ -11,8 +11,8 @@
 extern "C" {
 #endif
 
-const char* gVERSION;
-const char* gVERSION_SHORT;
+extern const char* gVERSION;
+extern const char* gVERSION_SHORT;
 
 #ifdef __cplusplus
 }

Build and install mraa. 

root@rock-4c-plus:/home/rock# mkdir build
root@rock-4c-plus:/home/rock# cd build/
root@rock-4c-plus:/home/rock# cmake ..
root@rock-4c-plus:/home/rock# make
rooroot@rock-4c-plus:/home/rock# make install
root@rock-4c-plus:/home/rock# ldconfig
root@rock-4c-plus:/home/rock# mraa-gpio version
Version v2.1.0 on ROCK Pi 4


Install example: Install Mraa on ROCK Pi 4B Debian11 armhf system

For Debian11 Distribution the below commands install the essential set: 

root@rockpi-4b:/home/rock# apt-get install -y git build-essential swig4.0 python-dev cmake libnode-dev python3-dev pkg-config tree
root@rockpi-4b:/home/rock# apt-get install -y libc6 libjson-c5 libjson-c-dev libgtest-dev libgcc1 libstdc++6 python python2.7 libpython2.7 python3.9 libpython3.9
root@rockpi-4b:/home/rock# apt-get install -y libgtest-dev pkg-config cmake-data

Get source code. 

root@rockpi-4b:/home/rock# git clone -b master https://github.com/radxa/mraa.git
root@rockpi-4b:/home/rock# cd mraa

Patch the source code for building mraa. 


diff --git a/CMakeLists.txt b/CMakeLists.txt
index 250d910..9050100 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required (VERSION 2.8.11)
+cmake_minimum_required (VERSION 3.14.0)
 project (mraa C CXX)
 
 FIND_PACKAGE (Threads REQUIRED)
@@ -9,6 +9,8 @@ if (CMAKE_VERSION VERSION_LESS "3.1")
   endif ()
 else ()
   set (CMAKE_C_STANDARD 99)
+  cmake_policy(SET CMP0078 OLD)
+  cmake_policy(SET CMP0086 NEW)
 endif ()
 
 ###############################################################################
diff --git a/include/version.h b/include/version.h
index 47366ef..3a567a1 100644
--- a/include/version.h
+++ b/include/version.h
@@ -11,8 +11,8 @@
 extern "C" {
 #endif
 
-const char* gVERSION;
-const char* gVERSION_SHORT;
+extern const char* gVERSION;
+extern const char* gVERSION_SHORT;
 
 #ifdef __cplusplus
 }

Build and install mraa 

root@rockpi-4b:/home/rock/mraa# mkdir build
root@rockpi-4b:/home/rock/mraa# cd build
root@rockpi-4b:/home/rock/mraa/build# cmake ..
root@rockpi-4b:/home/rock/mraa/build# make
root@rockpi-4b:/home/rock/mraa/build# make install
root@rockpi-4b:/home/rock/mraa/build# ldconfig
root@rockpi-4b:/home/rock/mraa/build# mraa-gpio version
Version v2.1.0-25-gf854463 on ROCK Pi 4

Backup prebuilt mraa on directory output. 

root@rockpi-4b:/home/rock/mraa/build# mkdir output
root@rockpi-4b:/home/rock/mraa/build# make install DESTDIR=output
root@rockpi-4b:/home/rock/mraa/build# tree output

Use mraa

Since we have installed mraa successfully, now we start to use it. At this part, you can check out the following guides.

Troubleshooting

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