namespace mysql {
#include <my_global.h>
#include <mysql.h>
}

/***************************************************************************
*   COSH 
* 
*   This file was made by Roland Bouman in response to Valeriy Kravchuk's 
*   request for feedback concerning bug 15439.
*
*   This is a bogus implementation of the hyperbolic cosine function.
*   In the original file, it attempts to minimic the behaviour of Oracle's
*   COSH function. 
*   During this process some bugs were encountered in the MySQL handling of
*   UDF definition. The exact same buggy behaviour can be observed using this 
*   file. Below, a sequence of SQL statements is printed that were executed
*   with this file, not the original.
*
*   Implementing it as a MySQL UDF has led to two different problems sofar.
*   
*   At first it was created as cosh (no capital H).
*   Whenever it was called, it always returned 1.0
*   This is a truly bizarre result, because our UDF returns a constant 0.0
*   It appeared as if our own function cosh never got called.
*   (I will file a separate bug report for that one)
*
*   By coincidence, it was found that creating the function with a capital H
*   does work as expected.
*   However, it has to be created referring to cosH (with the capital H); 
*   This holds true even if the function name is not quoted.
*
*   The function can then be dropped referring to just cosh (no Capital)
*   From then on, the function cosH is no longer accessible. 
*   For instance, it cannot be dropped again.
*   However, the corresponding entry in the mysql.func table remains.
*   As a result, recreating the function fails:
*
*   ERROR 1026 (HY000): Error writing file 'mysql.func' (errno: 121)
*
*   At this point, one can manually delete the offending entry from the 
*   mysql.func table; after that, all's well again as far as could be observed.
*
*   May the following script clarify the problem
*
    use mysql;
    Database changed
    select * from func;
    Empty set (0.00 sec)

    create function cosh returns real soname 'MySQLUDFCosHBug.dll';
    ERROR 1127 (HY000): Can't find function 'cosh' in library'
    create function cosH returns real soname 'MySQLUDFCosHBug.dll';
    Query OK, 0 rows affected (0.00 sec)

    select * from func;
    +------+-----+---------------------+----------+
    | name | ret | dl                  | type     |
    +------+-----+---------------------+----------+
    | cosH |   1 | MySQLUDFCosHBug.dll | function |
    +------+-----+---------------------+----------+
    1 row in set (0.00 sec)

    select cosh();
    +------------------+
    | cosh()           |
    +------------------+
    | 0.00000000000000 |
    +------------------+
    1 row in set (0.00 sec)

    drop function cosh;
    Query OK, 0 rows affected (0.00 sec)

    select cosh();
    ERROR 1305 (42000): FUNCTION mysql.cosh does not exist
    select * from func;
    +------+-----+---------------------+----------+
    | name | ret | dl                  | type     |
    +------+-----+---------------------+----------+
    | cosH |   1 | MySQLUDFCosHBug.dll | function |
    +------+-----+---------------------+----------+
    1 row in set (0.00 sec)

    drop function `cosH`;
    ERROR 1305 (42000): FUNCTION mysql.cosH does not exist
    create function cosH returns real soname 'MySQLUDFCosHBug.dll';
    ERROR 1026 (HY000): Error writing file 'mysql.func' (errno: 121)
    delete from func where name = 'cosH';
    Query OK, 1 row affected (0.00 sec)

    select * from func;
    Empty set (0.00 sec)
*
*
***************************************************************************/
extern "C" __declspec (dllexport) mysql::my_bool cosh_init(
    mysql::UDF_INIT* initid
,   mysql::UDF_ARGS* args
,   char *message
){ 
    initid->decimals = 14;
    initid->max_length = 32;
    return 0; 
}

extern "C" __declspec (dllexport) double cosh(
    mysql::UDF_INIT *initid
,   mysql::UDF_ARGS *args
,   char *is_null
,   char *error
){
    return 12.0;
}