无法找到mysql.h文件

Question

我正在尝试在ubuntu 12.04中安装c ++和mysql之间的连接.我安装了mysql-client,mysql-server,libmysqlclient15-dev,libmysql ++ - dev.但是当我尝试编译代码时,我得到了错误:mysql.h there is no such file.我看着文件夹,有mysql.h文件,我无法理解为什么它找不到它.这是我的代码:

 /* 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);
    }

它工作,但现在我面临另一个错误,如:

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

Answer 1

Ubuntu包中的mysql.h文件libmysqlclient-dev位于/usr/include/mysql/mysql.h.

这不是编译器的标准搜索路径,但是/usr/include.

您通常会mysql.h在代码中使用标头,如下所示:

#include <mysql/mysql.h>

如果您不想在源中指定目录偏移量,可以将-I标志传递给gcc(如果这就是您正在使用的)以指定其他包含搜索目录,然后您不需要更改现有代码.

例如.

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

Answer 2

只是用

$ apt-get install libmysqlclient-dev 

这会自动拉出最新的libmysqlclient18-dev

我已经看到旧版本的libmysqlclient-dev(如15)将mysql.h放在奇怪的位置,例如/ usr/local/include等.

否则,只是做一个

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

并将mysql.h带-I标志的文件夹路径放在make文件中.不干净但会起作用.

Answer 3

对于CentOS/RHEL:

yum install mysql-devel -y

Answer 4

这对我有用

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

-lmysqlclient 是必须的。

我建议使用以下符号而不是使用 -I 编译标志。

#include <mysql/mysql.h>