Change the logical line number. line-number must be an absolute expression. The next line has that logical line number. Therefore any other statements on the current line (after a statement separator character) are reported as on logical line number line-number − 1. One day as will no longer support this directive: it is recognized only for compatibility with existing assembler programs.
Warning: In the AMD29K configuration of as, this command is not available; use the synonym .ln in that context.
Even though this is a directive associated with the a.out or b.out object-code formats, as still recognizes it when producing COFF output, and treats .line as though it were the COFF .ln if it is found outside a .def/.endef pair.
Inside a .def, .line is, instead, one of the directives used by compilers to generate auxiliary symbol information for debugging.