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MySQL 5.7 Reference Manual
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int mysql_options4(MYSQL *mysql, enum mysql_option option, const void *arg1, const void *arg2)


mysql_options4() is similar to mysql_options() but has an extra fourth argument so that two values can be passed for the option specified in the second argument.

The following list describes the permitted options, their effect, and how arg1 and arg2 are used.

  • MYSQL_OPT_CONNECT_ATTR_ADD (argument types: char *, char *)

    This option adds a key/value pair to the current set of connection attributes to be passed to the server at connect time. Both arguments are pointers to null-terminated strings. The first and second strings indicate the key and value, respectively. If the key already exists in the current set of connection attributes, an error occurs. Comparison of the key name with existing keys is case sensitive.

    Key names that begin with an underscore (_) are reserved for internal use and should not be used by application programs.

    See also the descriptions for the MYSQL_OPT_CONNECT_ATTR_RESET MYSQL_OPT_CONNECT_ATTR_DELETE options in the description of the mysql_options() function.

    Connection attributes are exposed through the session_connect_attrs and session_account_connect_attrs Performance Schema tables. See Section 21.9.9, “Performance Schema Connection Attribute Tables”.

Return Values

Zero for success. Nonzero if you specify an unknown option.


This example demonstrates the calls that specify connection attributes:

MYSQL mysql;

mysql_options(&mysql,MYSQL_OPT_CONNECT_ATTR_RESET, 0);
mysql_options4(&mysql,MYSQL_OPT_CONNECT_ATTR_ADD, "key1", "value1");
mysql_options4(&mysql,MYSQL_OPT_CONNECT_ATTR_ADD, "key2", "value2");
mysql_options4(&mysql,MYSQL_OPT_CONNECT_ATTR_ADD, "key3", "value3");
mysql_options(&mysql,MYSQL_OPT_CONNECT_ATTR_DELETE, "key1");
if (!mysql_real_connect(&mysql,"host","user","passwd","database",0,NULL,0))
    fprintf(stderr, "Failed to connect to database: Error: %s\n",
mysql_options(&mysql,MYSQL_OPT_CONNECT_ATTR_RESET, 0);

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