Error compiling for board Arduino/Genuino Uno.

Projects Programming
1

I was trying to connect Mysql with Arduino Uno board. The code is as follows:
#include <mysql.h>

char *host, *user, *pass, *db;
int isconnected = 0;

void setup()
{
Serial.begin(9600);
host = "localhost";
user = "Aashi";
pass = "Aashi";
db = "test_arduino";
isconnected = mysql_connect(host,user,pass,db);
if(isconnected){
Serial.print("Connected to ");
Serial.println(host);
}
else{
Serial.println("Connection failed.");
}
mysql_close();
}

void loop(){}

And the errror messages are:
Arduino: 1.6.12 (Windows 10), Board: "Arduino/Genuino Uno"

C:\Users\Sushil Garg\Desktop\connection\connection.ino: In function 'void setup()':

C:\Users\Sushil Garg\Desktop\connection\connection.ino:30:7: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]

host = "localhost";

^

C:\Users\Sushil Garg\Desktop\connection\connection.ino:31:7: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]

user = "Aashi";

^

C:\Users\Sushil Garg\Desktop\connection\connection.ino:32:7: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]

pass = "Aashi";

^

C:\Users\Sushil Garg\Desktop\connection\connection.ino:33:5: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]

db = "test_arduino";

^

C:\Program Files (x86)\Arduino\libraries\mysql\mysql.cpp: In function 'int mysql_connect(char*, char*, char*, char*)':

C:\Program Files (x86)\Arduino\libraries\mysql\mysql.cpp:31:5: error: redefinition of 'int mysql_connect(char*, char*, char*, char*)'

int mysql_connect(char *host, char *user, char *pass, char *db){

^

C:\Program Files (x86)\Arduino\libraries\mysql\mysql.cpp:10:5: note: 'int mysql_connect(char*, char*, char*, char*)' previously defined here

int mysql_connect(char *host, char *user, char *pass, char *db){

^

C:\Program Files (x86)\Arduino\libraries\mysql\mysql.cpp: In function 'String mysql_result_query(String, String)':

C:\Program Files (x86)\Arduino\libraries\mysql\mysql.cpp:67:10: error: converting to 'String' from initializer list would use explicit constructor 'String::String(int, unsigned char)'

return 0;

^

C:\Program Files (x86)\Arduino\libraries\mysql\mysql.cpp:71:10: error: converting to 'String' from initializer list would use explicit constructor 'String::String(int, unsigned char)'

return 0;

^

exit status 1
Error compiling for board Arduino/Genuino Uno.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

I am using XAMPP web server and Windows 10. Please help.

2

Please post a link to where you downloaded the mysql library from. Use the chain link icon on the toolbar to make the link clickable. Or if you got it from Library Manager then state that and what the full name of the library is.

Please use code tags (</> button on the toolbar) when you post code or warning/error messages. The reason is that the forum software can interpret parts of your code as markup, leading to confusion, wasted time, and a reduced chance for you to get help with your problem. This will also make it easier to read your code and to copy it to the IDE or editor. Using code tags and other important information is explained in the How to use this forum post. Please read it.

Please always do a Tools > Auto Format on your code before posting it. This will make it easier for you to spot bugs and make it easier for us to read.

3

The first three messages are NOT errors. They are warnings. You are trying to assign a const char * pointer to a char * pointer. The compiler is warning you that that may not be a good idea, and that you need to think about what you are doing. If you KNOW that it is OK, use an explicit cast to tell the compiler that you know what you are doing.

The rest of the messages are telling you that the library stupidly uses the String class.

localhost is a name to be used when the client (the Arduino) and the server (where the MySQL database lives) are the same machine. You most certainly do NOT have the MySQL database program running on the Arduino, so localhost is WRONG!

4 
C:\Program Files (x86)\Arduino\libraries\mysql\mysql.cpp:31:5: error: redefinition of 'int mysql_connect(char*, char*, char*, char*)'

 int mysql_connect(char *host, char *user, char *pass, char *db){

     ^

C:\Program Files (x86)\Arduino\libraries\mysql\mysql.cpp:10:5: note: 'int mysql_connect(char*, char*, char*, char*)' previously defined here

 int mysql_connect(char *host, char *user, char *pass, char *db){

     ^

Looks like the library has mysql_connect() declared on line 10 and line 31.