The %LINE directive specifies that the next line should be treated in messages and in information generated for debugging as if it came from the specified line and file.
The characters '%LINE' must be in columns 1 through 5 of the input line for the directive to be recognized (and conversely, any line starting with these five characters is treated as a %LINE directive). The line-number must be an integral value of seven digits or less and the file-specification must not be enclosed in quotes. Any characters specified after the semicolon are ignored.
An example of what these lines should look like can be obtained by compiling a program with the options PPTRACE MACRO and MDECK.