On Friday 19 November 2004 16:16, Tom Lane wrote:
> This code is wrong on its face. If your compiler doesn't give a warning
> along the lines of "use of uninitialized value", get a better compiler.
> (Note: when using gcc I think you must specify -O to get this warning.
> I always use at least -O -Wall when developing with gcc.)
>
> > This will give me NOTICE: result=alignres_out.
>
> Pure luck that it doesn't crash instead. Apparently you're picking up a
> value that happened to be left in a register by the function-call
> manager, but on another machine or after any slight mod to fmgr.c that
> register might contain something that's not a pointer to string at all.
>
> regards, tom lane
Ok, the example wasnt complete, i just tried to show what i meant, so i try
again with the hole example. Now i use the \O and it gives no warnings.
Datum alignres_out(PG_FUNCTION_ARGS) {
alignres *align = (alignres *) PG_GETARG_POINTER(0);
char *result = NULL;
int secondStart=align->secondString;
elog(NOTICE, "secondStart=%d", secondStart);
char temp[4+strlen(align->stringBuffer)+4+4];
char tempBuffer[strlen(align->stringBuffer)+1];
char *first = NULL;
elog(NOTICE, "1:first=%s", first);
first = palloc(sizeof(char)*secondStart);
elog(NOTICE, "2:first=%s", first);
elog(NOTICE, "strlen(first)=%d", strlen(first));
snprintf(tempBuffer, sizeof(tempBuffer), "%s", align->stringBuffer);
first = strncpy(first, tempBuffer, secondStart-1);
snprintf(temp, sizeof(temp), "(%d, %s)",
align->value,
first);
result = (char*) palloc(strlen(temp)+1);
strcpy(result, temp);
PG_RETURN_CSTRING(result);
}
On the first elog i get (null) and thats correct. After the allocation i get
alignres_out. When i print out the variable secondString it is 5, but when i
print out the length of the first it is set to 12, the length of
"alignres_out".
Am i still doing something wrong? If so, how am i supposed to do it to get it
correct?
-Kjetil