Name
bif_arg , bif_array_arg , bif_array_or_null_arg , bif_bin_arg ,
bif_double_arg , bif_entity_arg , bif_float_arg , bif_long_arg ,
bif_long_or_char_arg , bif_string_arg , bif_string_or_null_arg ,
bif_string_or_wide_or_null_arg , bif_strses_arg — Get parameters
for built in function
Synopsis
caddr_t bif_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_array_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_array_or_null_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_bin_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_double_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_entity_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_float_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_long_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_long_or_char_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_string_arg ( |
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_string_or_null_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_string_or_wide_or_null_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
caddr_t bif_strses_arg ( |
caddr_t * qst , |
|
state_slot_t ** args , |
|
int nth , |
|
char * func ) ; |
Description
The bif_...._arg functions are used in the Virtuoso shared
object. They allow customization of the Virtuoso server. They are
written in C code, and linked with the Virtuoso shared object.
The _or_null_ variants of these functions represent the SQL null
value as a 00 pointer, even though getting the same argument with
bif_arg() would return a box with the DV_DB_NULL tag. All number
functions will coerce other types of numbers to the result type.
All array argument functions will accept any type of array. It is
up to the VSE itself to distinguish.
Virtuoso Server Extensions (VSEs) were formally referred to as
Built-In Functions (BIFs).
Parameters
nth
which argument to retrieve (zero indexed).
func
name of calling function. This will be printed in the SQL error
message.
Return Values
On success, return a valid pointer to the data retrieved, or
NULL. A SQL error is generated if the datatype is not valid. The
bif_arg is the only function not to have validation of a data
type.
The values returned by any of these belong to the query
instance, and the bif is not authorized to modify or free them.
Table24.5.Return
types
Function |
Type validated and returned |
bif_arg |
Any type of data. (no data type check) |
bif_array_arg |
string or array data |
bif_array_or_null_arg |
string or array or NULL data |
bif_bin_arg |
binary data |
bif_double_arg |
double data |
bif_entity_arg |
XML entity data |
bif_float_arg |
float data |
bif_long_arg |
long data |
bif_long_or_char_arg |
long or character data |
bif_string_arg |
string data |
bif_string_or_null_arg |
string or null data |
bif_string_or_wide_or_null_arg |
strings, widestrings or null data |
bif_strses_arg |
string session data |
Examples
Example24.22.Creating a
function my_length()
A function called my_length
written by developers, may process a string argument by making a
call to bif_string_arg
.