mysql UDF return INT instead of STRING

Question

I am having a problem using a User Defined Function in mysql 5.7.13 (Linux) :

This function is defined in mysql using :

CREATE FUNCTION PHPParse RETURNS STRING SONAME 'php_parser.so'

The C (& C++) file are the following :

my_bool PHPParse_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
void PHPParse_deinit(UDF_INIT *initid);
char* PHPParse(UDF_INIT *initid, UDF_ARGS *args, char *result, unsigned long *length, char *is_null, char *error);


my_bool PHPParse_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
{
  initid->maybe_null = 1;
  if (args->arg_count != 2 || args->arg_type[0] != STRING_RESULT || args->arg_type[1] != STRING_RESULT)
  {
    strcpy(message,"PHPParse (p_field_name, p_php_parser_string)");
    return 1;
  }
  initid->max_length=256;
  return 0;
}


char* PHPParse(UDF_INIT *initid MY_ATTRIBUTE((unused)), UDF_ARGS *args, char *result, unsigned long *length,char *is_null, char *error MY_ATTRIBUTE((unused)))
{
    *is_null = 0;
    memcpy(result,"begginning",10);
    *length= (unsigned long)(10);
    return result;
}

If I use the following SQL Query :

SELECT PHPParse('hello','222') as `date` FROM invoices ;

I get this result :

date:
62656767696e6e696e67
62656767696e6e696e67
62656767696e6e696e67
62656767696e6e696e67
etc...

While it would be supposed to return begginning

Where am i wrong ?

P.S Compile command :

g++  -std=c++11 -fPIC  -shared -I/usr/include/mysql -o /usr/lib64/mysql/plugin/php_parser.so  include/PHPSerializedDataLoader.cpp PHPParse.cc

score 1 · Answer 1 · answered Jul 27 '16 at 16:36

1

In case anyone is interested, a quick "patch" is to cast to string :

SELECT CAST(PHPParse(`serialized_infos`, '22')  AS CHAR CHARACTER SET utf8) as date1 FROM invoices

answered Jul 27 '16 at 16:36

Charles-Ugo Brouillard

221
1
9

mysql UDF return INT instead of STRING

1 Answers1