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(g77-300.info)Fortran 90 Features

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Fortran 90 Features
===================

   For convenience this section collects a list (probably incomplete) of
the Fortran 90 features supported by the GNU Fortran language, even if
they are documented elsewhere.  Note: Characters, Lines, and Execution
Sequence, for information on additional
fixed source form lexical issues.  Further, the free source form is
supported through the `-ffree-form' option.  Other Fortran 90 features
can be turned on by the `-ff90' option; see Note: Fortran 90.  For
information on the Fortran 90 intrinsics available, see Note: Table of
Intrinsic Functions.

Automatic arrays in procedures

Character assignments
     In character assignments, the variable being assigned may occur on
     the right hand side of the assignment.

Character strings
     Strings may have zero length and substrings of character constants
     are permitted.  Character constants may be enclosed in double
     quotes (`"') as well as single quotes.  Note: Character Type.

Construct names
     (Symbolic tags on blocks.)  Note: Construct Names.

`CYCLE' and `EXIT'
     Note: The `CYCLE' and `EXIT' Statements.

`DOUBLE COMPLEX'
     Note: `DOUBLE COMPLEX' Statement.

`DO WHILE'
     Note: DO WHILE.

`END' decoration
     Note: Statements.

`END DO'
     Note: END DO.

`KIND'

`IMPLICIT NONE'

`INCLUDE' statements
     Note: INCLUDE.

List-directed and namelist I/O on internal files

Binary, octal and hexadecimal constants
     These are supported more generally than required by Fortran 90.
     Note: Integer Type.

`O' and `Z' edit descriptors

`NAMELIST'
     Note: NAMELIST.

`OPEN' specifiers
     `STATUS='REPLACE'' is supported.  The `FILE=' specifier may be
     omitted in an `OPEN' statement if `STATUS='SCRATCH'' is supplied.

`FORMAT' edit descriptors
     The `Z' edit descriptor is supported.

Relational operators
     The operators `<', `<=', `==', `/=', `>' and `>=' may be used
     instead of `.LT.', `.LE.', `.EQ.', `.NE.', `.GT.' and `.GE.'
     respectively.

`SELECT CASE'
     Not fully implemented.  *Note `SELECT CASE' on `CHARACTER' Type:
     SELECT CASE on CHARACTER Type.

Specification statements
     A limited subset of the Fortran 90 syntax and semantics for
     variable declarations is supported, including `KIND'.  Note: Kind
     Notation.  (`KIND' is of limited usefulness in the absence of the
     `KIND'-related intrinsics, since these intrinsics permit writing
     more widely portable code.)  An example of supported `KIND' usage
     is:
          INTEGER (KIND=1) :: FOO=1, BAR=2
          CHARACTER (LEN=3) FOO
     `PARAMETER' and `DIMENSION' attributes aren't supported.