CodeIgniter User Guide Version 1.7

Common Functions

CodeIgniter uses a few functions for its operation that are globally defined, and are available to you at any point. These do not require loading any libraries or helpers.


is_writable() returns TRUE on Windows servers when you really can't write to the file as the OS reports to PHP as FALSE only if the read-only attribute is marked. This function determines if a file is actually writable by attempting to write to it first. Generally only recommended on platforms where this information may be unreliable.

if (is_really_writable('file.txt'))
    echo "I could write to this if I wanted to";
    echo "File is not writable";


The Config library is the preferred way of accessing configuration information, however config_item() can be used to retrieve single keys. See Config library documentation for more information.

show_error('message'), show_404('page'), log_message('level', 'message')

These are each outlined on the Error Handling page.