initial commit

ReadMe.md

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+Step 1:
+
+Create hello.cpp and hello.h and add the implementation.
+
+Example files are in lib folder.
+
+Step 2: 
+
+Make the archive file (.a) using xtensa-esp32-elf-gcc.exe for ESP32 and use xtensa-lx106-elf-gcc for ESP8266
+
+xtensa-esp32-elf-gcc.exe -c hello.cpp -o libhello.o
+xtensa-esp32-elf-ar.exe crf libhello.a libhello.o
+
+Note: xtensa-esp32-elf-gcc.exe is located here if you have installed ESP32 in your arduino IDE. 
+You may want to add this path to system env for easy access.
+C:\Users\<USERNAME>\AppData\Local\Arduino15\packages\esp32\tools\xtensa-esp32s2-elf-gcc\gcc8_4_0-esp-2021r2-patch3\bin\
+
+Now you should have a libhello.a in the path.
+
+Step 3: 
+1. Make the library for Ardunio (arduino-helloworld-lib) and copy the header files (lib\hello.h) to library src folder (arduino-helloworld-lib\src). 
+2. Copy the libhello.a to arduino-helloworld-lib\src\esp32 or arduino-helloworld-lib\src\esp8266 depending on which gcc you use to create the archive file.
+
+Step 4: 
+
+Invoke the function from Ardunio sketch. example.ino
+
+#include <hello.h> // hello.h header from our library  (arduino-helloworld-lib)
+
+#define BAUD_RATE  9600
+
+void setup() {
+   Serial.begin(BAUD_RATE);
+  
+}
+
+void loop() {
+  // put your main code here, to run repeatedly:
+   int result = add(1, 1); // Invokes the add function in libhello.a 
+   Serial.println(result);
+   delay(1000);
+}
+
+
+
+
+
+
+
+
+
+

arduino-helloworld-lib/library.properties

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+name=hello
+version=1.0.0
+author=aruna
+maintainer=aruna
+sentence=A simple library
+architectures=esp32
+includes=hello.h
+paragraph=
+precompiled=true
+url=https://www.sinric.com

arduino-helloworld-lib/src/hello.h

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+#ifndef HELLO_H
+#define HELLO_H
+
+int add(int x, int y);
+
+#endif

example/example.ino

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+#include <hello.h>
+
+#define BAUD_RATE  9600
+
+void setup() {
+   Serial.begin(BAUD_RATE);
+  
+}
+
+void loop() {
+  // put your main code here, to run repeatedly:
+   int result = add(1, 1);
+   Serial.println(result);
+   delay(1000);
+}

lib/hello.cpp

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+#include "hello.h"
+
+int add(int x, int y) {
+ return x + y;
+} 
+
+// C:\Users\user\AppData\Local\Arduino15\packages\esp32\tools\xtensa-esp32-elf-gcc\gcc8_4_0-esp-2021r2-patch3\bin
+// xtensa-esp32-elf-gcc.exe -c hello.cpp -o hello.o
+// xtensa-esp32-elf-ar.exe crf hello.a hello.o

lib/hello.h

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+#ifndef HELLO_H
+#define HELLO_H
+
+int add(int x, int y);
+
+#endif