test.h

MySQL用户自定义函数的使用示例: 详细说明了整个过程.

#ifdef STANDARD
/* STANDARD is defined, don't use any mysql functions */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef __WIN__
typedef unsigned __int64 ulonglong;	/* Microsofts 64 bit types */
typedef __int64 longlong;
#else
typedef unsigned long long ulonglong;
typedef long long longlong;
#endif /*__WIN__*/
#else
#include <my_global.h>
#include <my_sys.h>
#include <m_string.h>		// To get strmov()
#endif
#include <mysql.h>
#include <ctype.h>

static pthread_mutex_t LOCK_hostname;

#ifdef HAVE_DLOPEN

/* These must be right or mysqld will not find the symbol! */

extern "C" my_bool MyTest_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
extern "C" void MyTest_deinit(UDF_INIT *initid);
extern "C" longlong MyTest(UDF_INIT *initid, UDF_ARGS *args,char *is_null, char *error);


#define MAXMETAPH 8

my_bool MyTest_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
{
  /*if (args->arg_count != 1 || args->arg_type[0] != STRING_RESULT)
  {
    strcpy(message,"Wrong arguments to metaphon;  Use the source");
    return 1;
  }
  initid->max_length=MAXMETAPH;*/
  return 0;
}

/****************************************************************************
** Deinit function. This should free all resources allocated by
** this function.
** Arguments:
** initid	Return value from xxxx_init
****************************************************************************/


void MyTest_deinit(UDF_INIT *initid)
{
}

/***************************************************************************
** UDF string function.
** Arguments:
** initid	Structure filled by xxx_init
** args		The same structure as to xxx_init. This structure
**		contains values for all parameters.
**		Note that the functions MUST check and convert all
**		to the type it wants!  Null values are represented by
**		a NULL pointer
** result	Possible buffer to save result. At least 255 byte long.
** length	Pointer to length of the above buffer.	In this the function
**		should save the result length
** is_null	If the result is null, one should store 1 here.
** error	If something goes fatally wrong one should store 1 here.
**
** This function should return a pointer to the result string.
** Normally this is 'result' but may also be an alloced string.
***************************************************************************/


longlong MyTest(UDF_INIT *initid, UDF_ARGS *args,char *is_null, char *error)
{
	return 0;
}

#endif /* HAVE_DLOPEN */