PointerToBuff

Description: This function returns a buffer containing the numeric data from the variables pointed at by each element of the array.

Returns: Buffer

Usage: Script or Steady State

Format: PointerToBuff(ArrayStart, N, Option, Size, Skip)

Parameters: ArrayStart { numeric } { required } { no default: }

Any numeric expression that specifies the starting array element. This array contains the pointers to the variables whose values will be written to a buffer. Unless specified, the lowest dimension of a multidimensional array is used is a pointer array element.

N { numeric } { required } { no default: }

Any numeric expression giving the number of array elements to convert starting at the element given by the first parameter. If N extends past the upper bound of the lowest array dimension, this computation will "wrap-around" and resume at element 0, until N elements have been processed.

Option { numeric } { required } { no default: }

Any numeric expression that specifies the format of the buffer write:

Option	Format
0	Unsigned binary (low byte first)
1	Signed binary (low byte first)
2	BCD (binary coded decimal) (low byte first)
3	ASCII octal (high byte first)
4	ASCII decimal (high byte first)
5	ASCII hex (high byte first)
6	ASCII floating point (high byte first)
7	IEEE float/double (low byte first)
8	<obsolete>
9	Allen-Bradley® PLC/3 floating point
10	VAX single precision floating point

For Options 7 and 9 the data is written as appropriate binary format.

Size is any numeric expression giving the number of digits in each datum; it has a different meaning for each option as indicated below:

Option	Size Meaning	Size Range
Binary types	Number of bits	1 - 32 bits
BCD	Number of 4-bit digits	1 - 8 digits
ASCII types	Number of bytes	1 - 32 bytes
Float types	Precision	1 for single precision, 2 for double precision

Skip is any numeric expression giving the number of buffer bits/digits/bytes to skip after writing each non-floating point element. For floating point types, this parameter must be set to 0.

Comments: This function may only be used with pointers pointing at numeric data. Any invalid array elements, or invalid data pointed at by array elements are written to the buffer as formatted zeroes. This function is useful for writing I/O drivers and saving arrays of data in RAM with a fraction of the memory requirement.

Example:

buff1 = PointerToBuff(dataPtr[0]{ Starting point in array },

100 { No. of elements to convert },

5 { Write as ASCII hex },

4 { Number of bytes per },

0 { No skip between writes });

This produces a formatted buffer 400 bytes long (100 four byte groups). Each 4 bytes is a hex number corresponding to a variable pointed at by an element in the array. Invalid array elements and invalid data are written as 0.