eldo_user

Eldo Control Language
Library of Functions for Tasks
fopen
Task function category: Functions Operating on Files
Returns a file variable if the file whose path is FILE_PATH has been successfully opened;
otherwise, the program exits printing the optional message DIE_MESSAGE.
Usage
fopen(FILE_PATH, MODE [, DIE_MESSAGE])
Arguments
• FILE_PATH
Path to file.
• MODE
MODE selects the open mode: "w" for write, "r" for read, or "a" for append (note that it is a
string). The file must already exist to be opened in read mode. In write mode, it will be
created if it does not exist, or overwritten if it already existed. In append mode, if the file
already exists it will be appended to.
• DIE_MESSAGE
Optional. Function exit message text.
Examples
If you want to append the same file multiple times during the execution of many tasks, instead
of using multiple fopen/fclose functions it is more efficient to keep the file always open and to
pass the file variable as a task parameter. To do so, it is necessary to define a main task that will
open the file and then call the subtasks with the file variable as a parameter, for example:
Eldo® User's Manual, 15.3 903