Section 14,40: comment

 Text that documents or explains a program, and begins with a letter
 C (or c) or an asterisk (*) in column 1 of a source line.  Note
 that the letter C can also denote a compiler directive.  A comment
 can also begin with an exclamation point (!), which can appear
 anywhere in a source line -- except in a Hollerith or character
 constant, in column 6 of a fixed-format line, or inside a
 placeholder (using the DESIGN compiler option on VMS on VAX).  The
 comment extends from the exclamation point to the end of the line.
 The Fortran compiler does not process comments, but shows them in
 program listings.  See also compiler_directive.