Re: [HACKERS] my strftime func doesn't work. please help.

Zsolt Varga writes:
> 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,
> ----------------------------------------------------------------------
> #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 );
> }

I don't see what is causing your failure, perhaps you might want to test
it under gdb. But, you are using malloc() way too much which will make this
quite slow and wastful of memory. Also, you probably should be using palloc()
not malloc() or it will cause the backend to leak memory. For example:

char *
pstrtime( char *format , DateADT val)
{
int year,
month,
day;
struct tm time1;
char buf[256];
char *result;

j2date(val + JDATE_2000, &year, &month, &day);
memset(time1, 0, sizeof(time1));
time1.tm_year = year;
time1.tm_mon = month-1;
time1.tm_mday = day;

strftime(buf, 90, format, &time1);

result = palloc(1 + strlen(buf));
if (result)
strcpy(result, buf, sizeof(buf))
return result;
}

-dg

David Gould dg(at)illustra(dot)com 510.628.3783 or 510.305.9468
Informix Software 300 Lakeside Drive Oakland, CA 94612
- A child of five could understand this! Fetch me a child of five.