my strftime func doesn't work. please help.

hello!

I tried to make a function, like strftime in C
called pstrtime( format, date )

here's the source... but when I compile it and create the function
under 6.3.2 first time it gives back an emty string.. after the backend
stops ;(

please correct my faults,
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#include <stdio.h> /* for sprintf() */
#include <string.h>
#include <limits.h>
#include "postgres.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/nabstime.h"
#include "utils/datetime.h"
#include "access/xact.h"

#define JDATE_2000 2451545

char *pstrtime(char *format, DateADT val);

char *
pstrtime( char *format , DateADT val)
{
int year,
month,
day;
struct tm * time1;
char *sometext;
sometext = malloc(100);
time1 = malloc(sizeof(struct tm));

j2date(val + JDATE_2000, &year, &month, &day);

time1->tm_year=year;
time1->tm_mon=month-1;
time1->tm_mday=day;

strftime(sometext,90,format,time1 );
free(time1);
return( sometext );
}

anyway how to create this function under psql ?
C type postgres type
-----------------------------------
DateADT date
char * ???????????

thanks,

Best regards,
Redax
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