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--- user:asowers:mysqldaemon [2013/04/21 23:27] – created asowers
+++ user:asowers:mysqldaemon [2013/04/21 23:28] (current) – [C code] asowers
@@ Line 1: / Line 1: @@
+====Welcome====
+====Purpose====
+The purpose of this project was to create a simple daemon type utility that checks the state of a MYSQL database. Based on the state of certain data the program will execute certain operations.
+====The GPIO====
+Using the wringPi library means you can use your RPi's GPIO like an Arduino's. This means easy access to the GPIO in C/C++ programs.
+the workhorse of wiringPi is: "pinMode(pinNumber, OUTPUT/INPUT);" and "digitalWrite(pinNumber, state);"
+====PHP and MYSQL====
+Using a PHP frontend and MYSQL as mediator we can have users interface with the RPi's GPIO via a web GUI. Let's abstract that away for now and focus on the daemon.
+====C code====
+Here's some code that establishes a local MYSQL connection and checks the database based on an interval of seconds chosen as an initial argument.
+<code c>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <wiringPi.h>
+#include </usr/include/mysql/mysql.h>
+int main(int argc, char *argv[]){
+char user[7] = "gpio";
+char pass[6] = "*****";
+MYSQL *connection;
+MYSQL_RES *result;
+MYSQL_ROW row;
+int num_fields;
+int i;
+if (wiringPiSetup () == -1)
+    exit (1) ;
+connection = mysql_init(NULL);
+if (connection == NULL) {
+      printf("Error %u: %s\n", mysql_errno(connection), mysql_error(connection));
+      exit(1);
+}else{
+printf("connection established\n");
+}
+printf("MySQL client version: %s\n", mysql_get_client_info());
+mysql_real_connect(connection, "localhost", user, pass, "gpio", 0, NULL, 0);
+int repeatFlag = atoi(argv[1]);
+char test[4];
+for(;;){
+	mysql_query(connection, "SELECT pinDirection FROM pinDirection WHERE pinNumber ='17'");
+	result = mysql_store_result(connection);
+	num_fields = mysql_num_fields(result);
+	while ((row = mysql_fetch_row(result)))
+  	{
+      		for(i = 0; i < num_fields; i++)
+      		{
+			char* tester = row[i] ? row[i] : "NULL";
+			if (tester[0] == 'o' && tester[1] == 'u' && tester[2] == 't'){
+				printf("%s\n",tester);
+				pinMode(0, OUTPUT);
+				mysql_query(connection, "SELECT pinStatus FROM pinStatus WHERE pinNumber ='17'");
+				result = mysql_store_result(connection);
+			        num_fields = mysql_num_fields(result);
+				tester = NULL;
+				while ((row = mysql_fetch_row(result))){
+					for(i = 0; i < num_fields; i++){
+						char *tester = row[i] ? row[i] : "NULL";
+						printf("State: %s\n",tester);
+						if (tester[0] == '0'){
+							digitalWrite(0, 0);
+						}else digitalWrite(0, 1);
+					}
+				}
+			}else if(tester[0] == 'i' && tester[1] == 'n'){
+				printf("%s\n",tester);
+				pinMode(0, INPUT);
+				mysql_query(connection, "SELECT pinStatus FROM pinStatus WHERE pinNumber ='17'");
+                                result = mysql_store_result(connection);
+                                num_fields = mysql_num_fields(result);
+				tester = NULL;
+                                while ((row = mysql_fetch_row(result))){
+                                        for(i = 0; i < num_fields; i++){
+                                        	char *tester = row[i] ? row[i] : "NULL";
+                                                printf("State%s\n",tester);
+                                                if (tester[0] == '0'){
+                                                        digitalWrite(0, 0);
+                                                }else digitalWrite(0, 1);
+                                        }
+                                }
+			}
+      		}
+      		printf("\n");
+  	}
+	sleep(repeatFlag);
+}
+mysql_free_result(result);
+mysql_close(connection);
+return 0;
+}
+</code>

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