Richard Massa wrote:
> Hi there,
>
> I'm getting a strange behaviour when returning a value from my user defined
> function. When I print the return value inside of the function, I get one
> answer (the correct one), however mysql reports a different value all together.
> Is this my programming error or a mysql bug?
>
> Here's what I'm seeing:
>
> In mysql:
>
> +-------------------------------------------------------------------------+
> | ddist(m.x, m.y, m.z, n.x, n.y, n.z, 30.0893021, 30.3757286, 32.6442299) |
> +-------------------------------------------------------------------------+
> | 0.72 |
> | 0.66 |
> | 0.61 |
> | 0.47 |
> +-------------------------------------------------------------------------+
>
> my hostname.err logfile where I print debugging info:
>
> result: 33.048230
> result: 9.203189
> result: 12.836390
> result: 9.615359
>
> Here's the source code for my program
>
> #include <stdio.h>
> #include <string.h>
> #include <my_global.h>
> #include <my_sys.h>
> #include <mysql.h>
> #include <m_ctype.h>
>
> #ifdef HAVE_DLOPEN
>
> extern "C" {
>
> my_bool ddist_init (UDF_INIT *initid, UDF_ARGS *args, char *message);
> void ddist_deinit (UDF_INIT *initid);
> double ddist (UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error);
>
> }
>
> void ddist_deinit(UDF_INIT *initid){}
>
> my_bool ddist_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
> {
> initid->decimals=2; // We want 2 decimals in the result
> initid->max_length=6; // 3 digits + . + 2 decimals
>
> return 0;
> /*
> int i=0; // counter
>
> if (!args->arg_count || args->arg_count != 9)
> {
> strcpy(message,"dist must have exactly nine arguments");
> return 2;
> }
>
> for ( i=0;i<6;i++ )
> {
> if ( args->arg_type[i] != REAL_RESULT )
> strcpy( message, "dist must be passed six real numbers");
> return 2;
> }
> */
> }
>
> double ddist(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
> {
> double xi, yi, zi, xj, yj, zj, cubex, cubey, cubez ; //variables for arguments
> int shiftx, shifty, shiftz; // temp variables
> double rijx, rijy, rijz; // temp variables
> double result; // result
>
> xi = *((double*)args->args[0]);
> yi = *((double*)args->args[1]);
> zi = *((double*)args->args[2]);
> xj = *((double*)args->args[3]);
> yj = *((double*)args->args[4]);
> zj = *((double*)args->args[5]);
>
> cubex = *((double*)args->args[6]);
> cubey = *((double*)args->args[7]);
> cubez = *((double*)args->args[8]);
>
> shiftx = int( rint( (xi-xj)/cubex ));
> shifty = int( rint( (yi-yj)/cubey ));
> shiftz = int( rint( (zi-zj)/cubez ));
> fprintf(stderr,"sx=%d, sy=%d, sz=%d, cx=%f, cy=%f, cz=%f, xi=%f, yi=%f, zi=%f,
> xj=%f, yj=%f, zj=%f\n",shiftx,shifty,shiftz,cubex,cubey,cubez,xi,yi,zi,xj,yj,zj);
>
> rijx = xi-xj-cubex*shiftx;
> rijy = yi-yi-cubey*shifty;
> rijz = zi-zj-cubez*shiftz;
> fprintf(stderr,"rijx=%f,rijy=%f,rijz=%f\n",rijx,rijy,rijz);
>
> result = sqrt( (rijx*rijx) + (rijy*rijy) + (rijz*rijz) );
>
> fprintf(stderr,"test: %f\n",(rijz*rijz));
> fprintf(stderr,"result: %f\n",result);
> return result;
> }
>
> #endif /* HAVE_DLOPEN */
>
> Here's what I'm using to compile:
>
> g++ -O3 -DDBUG_OFF -fno-implicit-templates -fno-exceptions -fno-rtti -shared
> -I/usr/include/mysql -rdynamic dist.cc -o dist.so
>
> Anyone have any ideas?
>
> Thanks,
> Richard
>
This is a question for mysql@stripped list.
--
Sincerely,
--
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