Here is an example of a simple C function that takes an INOUT string argument, strips off the first four characters, and returns the result. The external stored procedure uses parameter style TD_GENERAL.
/***** C source file name: getregion.c *****/
#define SQL_TEXT Latin_Text
#include <sqltypes_td.h>
#include <string.h>
void xsp_getregion( VARCHAR_LATIN *region,
char sqlstate[6])
{
char tmp_string[64];
if (strlen((const char *)region) > 4)
{
/* Strip off the first four characters */
strcpy(tmp_string, (char *)region);
strcpy((char *)region, &tmp_string[4]);
}
}