mysql.h file can't be found

Question

i'm trying to install connection between c++ and mysql in ubuntu 12.04. i've installed mysql-client, mysql-server, libmysqlclient15-dev, libmysql++-dev. but when i try to compile the code i got the error: mysql.h there is no such file. i looked in the folders, there is mysql.h file, i can't understand why it can't find it. here is my code:

 /* Simple C program that connects to MySQL Database server*/
    #include <mysql.h>
    #include <stdio.h>

    main() {
      MYSQL *conn;
      MYSQL_RES *res;
      MYSQL_ROW row;

      char *server = "localhost";
      char *user = "root";
      //set the password for mysql server here
      char *password = "*********"; /* set me first */
      char *database = "Real_flights";

      conn = mysql_init(NULL);

      /* Connect to database */
      if (!mysql_real_connect(conn, server,
            user, password, database, 0, NULL, 0)) {
          fprintf(stderr, "%s\n", mysql_error(conn));
          exit(1);
      }

      /* send SQL query */
      if (mysql_query(conn, "show tables")) {
          fprintf(stderr, "%s\n", mysql_error(conn));
          exit(1);
      }

      res = mysql_use_result(conn);

      /* output table name */
      printf("MySQL Tables in mysql database:\n");
      while ((row = mysql_fetch_row(res)) != NULL)
          printf("%s \n", row[0]);

      /* close connection */
      mysql_free_result(res);
      mysql_close(conn);
    }

it's worked, but now i'm facing another error like :

mysql.c: In function ‘main’:
mysql.c:21: warning: incompatible implicit declaration of built-in function ‘exit’
mysql.c:27: warning: incompatible implicit declaration of built-in function ‘exit’
/tmp/ccinQBp8.o: In function `main':
mysql.c:(.text+0x3e): undefined reference to `mysql_init'
mysql.c:(.text+0x5e): undefined reference to `mysql_real_connect'
mysql.c:(.text+0x70): undefined reference to `mysql_error'
mysql.c:(.text+0xa5): undefined reference to `mysql_query'
mysql.c:(.text+0xb7): undefined reference to `mysql_error'
mysql.c:(.text+0xe7): undefined reference to `mysql_use_result'
mysql.c:(.text+0x11c): undefined reference to `mysql_fetch_row'
mysql.c:(.text+0x133): undefined reference to `mysql_free_result'
mysql.c:(.text+0x141): undefined reference to `mysql_close'
collect2: ld returned 1 exit status

Solution 1

The mysql.h file from the libmysqlclient-dev Ubuntu package is located at /usr/include/mysql/mysql.h.

This is not a standard search path for compilers, however /usr/include is.

You'd typically use the mysql.h header in your code like this:

#include <mysql/mysql.h>

If you don't want to specify the directory offset in your source, you can pass the -I flag to gcc (If that's what you are using) to specify an additional include search directory, and then you wouldn't need to change your existing code.

eg.

gcc -I/usr/include/mysql ...

Solution 2

just use

$ apt-get install libmysqlclient-dev 

which will automatically pull the latest libmysqlclient18-dev

I have seen older versions of libmysqlclient-dev (like 15) puts the mysql.h in weird locations e.g. /usr/local/include etc.

otherwise, just do a

$ find /usr/ -name 'mysql.h' 

and put the folder path of your mysql.h with -I flag in your make file. Not clean but will work.

Solution 3

For CentOS/RHEL:

yum install mysql-devel -y

Solution 4

this worked for me

$ gcc dbconnect.c -o dbconnect -lmysqlclient
$ ./dbconnect

-lmysqlclient is must.

and i would recommend to use following notation instead of using -I compilation flag.

#include <mysql/mysql.h>

Solution 5

You have to let the compiler know where the mysql.h file can be found. This can be done by giving the path to the header before compiling. In IDEs you have a setting where you can give these paths.

This link gives you more info on what options to use while compiling.

To your second problem You need to link the libraries. The linker needs to know where the library files are which has the implementation for the mysql functions that you use.

This link gives you more info on how to link libraries.

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