GNU Fortran Character Set

(Corresponds to Section 3.1 of ANSI X3.9-1978 FORTRAN 77.)

Letters include uppercase letters (the twenty-six characters of the English alphabet) and lowercase letters (their lowercase equivalent). Generally, lowercase letters may be used in place of uppercase letters, though in character and Hollerith constants, they are distinct.

Special characters include:

• Semicolon (;)
• Exclamation point (!)
• Double quote (")
• Backslash (\)
• Question mark (?)
• Hash mark (#)
• Ampersand (&)
• Percent sign (%)
• Underscore (_)
• Open angle (<)
• Close angle (>)
• The FORTRAN 77 special characters (<SPC>, =, +, -, *, /, (, ), ,, ., $, ', and :)

Note that this document refers to <SPC> as space, while X3.9-1978 FORTRAN 77 refers to it as blank.