How to output a NVARCHAR data in UDF

[zhaoxu710]

Hi,

I want to return a data with the type NVARCHAR. How could I do it?

Here is my function :

II_STATUS
my_function(
   II_SCB          *scb,
   II_DATA_VALUE   *p1, /*type nvarchar*/
   II_DATA_VALUE   *p1, /*type nvarchar*/
   II_DATA_VALUE   *rdv /* return_text need nvarchar  */
){
	char str[400];
	unsigned char this_byte1[2],this_byte2[2],byte1[40], byte2[40];
	unsigned int true_length1,true_length2,iLen;
	unsigned short offset;
	offset=sizeof(short);
	int i;

true_length1 = *(short*)p1->db_data;
true_length2 = *(short*)p2->db_data;

memset(byte1, 0, sizeof(byte1));	
memset(this_byte1, 0, sizeof(this_byte1));
for (i=0; i < true_length1; i++) {
       	strncpy(this_byte1, (char *)(p1->db_data + offset + i*2), 2);
       	strcat(byte1,this_byte1);
  };

memset(byte2, 0, sizeof(byte2));
memset(this_byte2, 0, sizeof(this_byte2));
for (i=0; i < true_length2; i++) {
       	strncpy(this_byte2, (char *)(p2->db_data + offset + i*2), 2);
       	strcat(byte2,this_byte2);
  };

int iLen; 
memset(str, 0, sizeof(str));
strcpy(str,byte1);
iLen = strlen(byte1);
memcpy(str + iLen, ".", 1);
iLen += 1;
memcpy(str + iLen ,byte2,true_length2 );
iLen += true_length2;
*(short *) rdv->db_data = iLen;


//Here, I don't know how to input the value into (char *)rdv->db_data?
strcat((char *)rdv->db_data + offset, str);
}

Could someone read it and answer my question?
Mille thx for you.

Zhao Xu

[kschendel]

rdv->db_data will point to a DB_NVCHR_STRING structure, defined in iicommon.h (common/hdr/hdr). Your function wants to finish with something like:

DB_NVCHR_STRING *result;
...
result = (DB_NVCHR_STRING *) rdv->db_data;
result->count = length_in_characters;
memcpy(result->element_array, source, length_in_characters);

By the way, I'm not sure what your function does, but using strcpy, strcat, etc on nvarchar data is probably not a good idea. The characters in a DB_NVCHR_STRING are UCS2 and the likelihood of hitting a premature null byte is very high.

[zhaoxu710]

Hi kschendel,

Thx for your answer. As you say, I got the wrong result due to strcpy. And do you have any idea for getting the values of p1 and doing the operations like in my exemple code?

I'm blocked now.

Thx again for your help!

Zhao Xu