examples: Cleanup C++ examples

Modify the C++ examples to be of same coding standard like C. As a
part of this cleanup, a new LED example is also added.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

examples/c++/gpio.cpp

@@ -0,0 +1,114 @@
+/*
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ * Copyright (c) 2018 Linaro Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Example usage: Toggles GPIO's 23 and 24 recursively. Press Ctrl+C to exit
+ *
+ */
+
+/* standard headers */
+#include <iostream>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+/* mraa headers */
+#include "mraa/common.hpp"
+#include "mraa/gpio.hpp"
+
+/* gpio declaration */
+#define GPIO_PIN_1 23
+#define GPIO_PIN_2 24
+
+volatile sig_atomic_t flag = 1;
+
+void
+sig_handler(int signum)
+{
+    if (signum == SIGINT) {
+        std::cout << "Exiting..." << std::endl;
+        flag = 0;
+    }
+}
+
+int
+main(void)
+{
+    mraa::Result status;
+
+    /* install signal handler */
+    signal(SIGINT, sig_handler);
+
+    //! [Interesting]
+    /* initialize GPIO pin */
+    mraa::Gpio gpio_1(GPIO_PIN_1);
+
+    /* initialize GPIO pin */
+    mraa::Gpio gpio_2(GPIO_PIN_2);
+
+    /* set GPIO to output */
+    status = gpio_1.dir(mraa::DIR_OUT);
+    if (status != mraa::SUCCESS) {
+        printError(status);
+        return EXIT_FAILURE;
+    }
+
+    /* set gpio 24 to output */
+    status = gpio_2.dir(mraa::DIR_OUT);
+    if (status != mraa::SUCCESS) {
+        printError(status);
+        return EXIT_FAILURE;
+    }
+
+    /* toggle both GPIO's */
+    while (flag) {
+        status = gpio_1.write(1);
+        if (status != mraa::SUCCESS) {
+            printError(status);
+            return EXIT_FAILURE;
+        }
+        status = gpio_2.write(0);
+        if (status != mraa::SUCCESS) {
+            printError(status);
+            return EXIT_FAILURE;
+        }
+
+        sleep(1);
+
+        status = gpio_1.write(0);
+        if (status != mraa::SUCCESS) {
+            printError(status);
+            return EXIT_FAILURE;
+        }
+
+        status = gpio_2.write(1);
+        if (status != mraa::SUCCESS) {
+            printError(status);
+            return EXIT_FAILURE;
+        }
+
+        sleep(1);
+    }
+    //! [Interesting]
+
+    return EXIT_SUCCESS;
+}