The InterBase UDF Library

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InterBase provides a number of frequently needed functions in the form of a UDF library, named ib_udf.dll on Windows platforms and ib_udf on UNIX platforms. This UDF library is located in <<InterBase_home>>/UDF and its functions are all implemented using the standard C library. This section describes each UDF and provides its declaration.

Important notes:

• Do not move the UDF library file from its installed location unless you also move the utility file that is located in the same directory (ib_util.dll on Windows, ib_util.so on Solaris and Linux). The UDF library file requires the utility file to function correctly.
• There is a script, ib_udf.sql, in the <<InterBase_home>>/examples/udf directory that declares all of the functions listed below. If you want to declare only a subset of these, copy and edit the script file.
• Several of these UDFs must be called using the new FREE_IT keyword if, and only if, they are written in thread-safe form, using malloc to allocate dynamic memory.
• When trigonometric functions are passed inputs that are out of bounds, they return zero rather than NaN.

Below is a list of the functions supplied in the InterBase UDF library. The description and code for each function follow the table.

Function name	Description	Inputs	Outputs
abs	Absolute value	Double precision	Double precision
acos	Arc cosine	Double precision	Double precision
ascii_char	Return character based on ASCII code.	Integer	Char(1)
ascii_val	Returns the ASCII value of the character passed in.	Char(1)	Integer
io	Return ASCII code for given character.	Char(1)	Integer
asin	Arc sine	Double precision	Double precision
atan	Arc tangent	Double precision	Double precision
atan2	Arc tangent divided by second argument	Double precision, Double precision	Double precision
bin_and	Bitwise AND operation	Integer, Integer	Integer
bin_or	Bitwise OR operation	Integer, Integer	Integer
bin_xor	Bitwise XOR operation	Integer, Integer	Integer
ceiling	Round up to nearest whole value.	Double precision	Double precision
cos	Cosine	Double precision	Double precision
cosh	Hyperbolic cosine	Double precision	Double precision
cot	Cotangent	Double precision	Double precision
div	Integer division	Integer	Integer
floor	Round down to nearest whole value.	Double precision	Double precision
ln	Natural logarithm	Double precision	Double precision
log	Logarithm of the first argument, by the base of the second argument.	Double precision, Double precision	Double precision
log10	Logarithm base 10	Double precision	Double precision
lower	Reduce all upper-case characters to lower-case.	Cstring(80)	Cstring(80)
ltrim	Strip preceding blanks.	Cstring(80)	Cstring(80)
mod	Modulus operation between the two arguments.	Integer, Integer	Integer
pi	Return the value of p.	—	Double precision
rand	Return a random value.	—	Double precision
rtrim	Strip trailing blanks.	Cstring(80)	Cstring(80)
sign	Return -1, 0, or 1.	Double precision	Integer
sin	Sine	Double precision	Double precision
sinh	Hyperbolic sine	Double precision	Double precision
sqrt	Square root	Double precision	Double precision
strlen	Length of string	Cstring(80)	Integer
substr	The substring of <s> starting at position <m> and ending at position <n>.	Cstring(80), Smallint, Smallint	Cstring(80)
tan	Tangent	Double precision	Double precision
tanh	Hyperbolic tangent	Double precision	Double precision