By default you cannot write a print_r, var_dump, or debug_print_backtrace to a log in PHP. When you call these methods, PHP immediately echo’s out the data. Instead you must use PHPs ob_start which instructs PHP to not output anything from the script. To access the contents of the buffer use ob_get_contents and to let PHP know its okay to output from your script once again call ob_end_clean.
1 2 3 4 | ob_start(); var_dump(debug_backtrace()); $backtrace=ob_get_contents(); ob_end_clean(); |