examples: add component for protocol examples network functionality

* Original commit: espressif/esp-idf@22bef90bd3

examples/common_components/protocol_examples_common/stdin_out.c

@@ -0,0 +1,30 @@
+/* Common functions for protocol examples, to configure stdin and stdout.
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+ */
+
+#include "protocol_examples_common.h"
+#include "esp_err.h"
+#include "esp_vfs_dev.h"
+#include "driver/uart.h"
+#include "sdkconfig.h"
+
+esp_err_t example_configure_stdin_stdout()
+{
+    // Initialize VFS & UART so we can use std::cout/cin
+    setvbuf(stdin, NULL, _IONBF, 0);
+    setvbuf(stdout, NULL, _IONBF, 0);
+    /* Install UART driver for interrupt-driven reads and writes */
+    ESP_ERROR_CHECK( uart_driver_install( (uart_port_t)CONFIG_CONSOLE_UART_NUM,
+            256, 0, 0, NULL, 0) );
+    /* Tell VFS to use UART driver */
+    esp_vfs_dev_uart_use_driver(CONFIG_CONSOLE_UART_NUM);
+    esp_vfs_dev_uart_set_rx_line_endings(ESP_LINE_ENDINGS_CR);
+    /* Move the caret to the beginning of the next line on '\n' */
+    esp_vfs_dev_uart_set_tx_line_endings(ESP_LINE_ENDINGS_CRLF);
+    return ESP_OK;
+}