Basic Characteristics RAPID

Example
Limitations
Error handling
Predefined data
Syntax
The string that is read is then converted to a numeric value; e.g. “234.4” is converted
to the numeric value 234.4. If all the characters read are not digits, 0 is returned.
reg1 := ReadNum(infile);
IF reg1 > EOF_NUM THEN
TPWrite "The file is empty"
..
Before using the number read from the file, a check is performed to make sure
that the file is not empty.
The function can only be used for files that have been opened for reading.
If an access error occurs during reading, the system variable ERRNO is set to
ERR_FILEACC. If there is an attempt to read non numeric data, the system variable
ERRNO is set to ERR_RCVDATA. These errors can then be dealt with by the error
handler.
The constant EOF_NUM can be used to stop reading, at the end of the file.
CONST num EOF_NUM := 9.998E36;
ReadNum ’(’
[IODevice ’:=’]
[’\’Time’:=’ ]’)’
A function with a return value of the type num.
Related information
Described in:
Opening (etc.) serial channels RAPID Summary - Communication
9-ReadNum-2 RAPID Reference Manual