Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide

Line continuation

During compilation, any source line that is shorter than the value of the right-hand margin setting as defined by the MARGINS option is padded on the right with blank characters to make the line as long as the right-hand margin setting. For example, if you use the IBM-default MARGINS (2,72), any line less than 72 characters long is padded on the right to make the line 72 characters long.

If long identifier names extend beyond the right margin, you should put the entire name on the next line rather than try to split it between two lines.

If a line of your program exactly reaches the right-hand margin, the last character of that line is concatenated with the first character within the margins of the next line with no blank characters in between.

If you have a string that reaches beyond the right-hand margin setting, you can carry the text of the string on to the following line (or lines). It is recommended that long strings be split into a series of shorter strings (each of which fits on a line) that are concatenated together. For example, instead of coding this:

 do;
  if x > 200 then
   display ('This is a long string and requires more than one line to
    type it into my program');
  else
   display ('This is a short string');
 end;

You should use the following sequence of statements:

 do;
  if x > 200 then
   display ('This is a long string and requires more than '
    ||'one line to type it into my program');
  else
   display ('This is a short string');
 end;
Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide