re PR fortran/54339 (Update gfortran manual for GCC 4.8's TS29113 changes)
2013-02-07 Tobias Burnus <burnus@net-b.de>
PR fortran/54339
* gfortran.texi (Standards): Mention TS29113.
(Varying Length Character): Mention deferred-length
strings.
(Fortran 2003 Status): Add unlimited polymorphic.
(TS 29113 Status): Add TYPE(*) and DIMENSION(..).
(C Interop): Update the section about TS29113.
From-SVN: r195845
This commit is contained in:
Tobias Burnus
Tobias Burnus
parent
0b8e955a11
commit
3e50813114
|
|
@ -1,3 +1,13 @@
|
|||
2013-02-07 Tobias Burnus <burnus@net-b.de>
|
||||
|
||||
PR fortran/54339
|
||||
* gfortran.texi (Standards): Mention TS29113.
|
||||
(Varying Length Character): Mention deferred-length
|
||||
strings.
|
||||
(Fortran 2003 Status): Add unlimited polymorphic.
|
||||
(TS 29113 Status): Add TYPE(*) and DIMENSION(..).
|
||||
(C Interop): Update the section about TS29113.
|
||||
|
||||
2013-02-06 Paul Thomas <pault@gcc.gnu.org>
|
||||
|
||||
PR fortran/55789
|
||||
|
|
|
|||
|
|
@ -221,7 +221,7 @@ compiler.
|
|||
|
||||
The GNU Fortran compiler front end was
|
||||
designed initially as a free replacement for,
|
||||
or alternative to, the unix @command{f95} command;
|
||||
or alternative to, the Unix @command{f95} command;
|
||||
@command{gfortran} is the command you will use to invoke the compiler.
|
||||
|
||||
@menu
|
||||
|
|
@ -522,12 +522,13 @@ ISO/IEC 1539:1997 (Fortran 95). As such, it can also compile essentially all
|
|||
standard-compliant Fortran 90 and Fortran 77 programs. It also supports
|
||||
the ISO/IEC TR-15581 enhancements to allocatable arrays.
|
||||
|
||||
In the future, the GNU Fortran compiler will also support ISO/IEC
|
||||
1539-1:2004 (Fortran 2003), ISO/IEC 1539-1:2010 (Fortran 2008) and
|
||||
future Fortran standards. Partial support of the Fortran 2003 and
|
||||
Fortran 2008 standard is already provided; the current status of the
|
||||
support is reported in the @ref{Fortran 2003 status} and
|
||||
@ref{Fortran 2008 status} sections of the documentation.
|
||||
GNU Fortran also have a partial support for ISO/IEC 1539-1:2004 (Fortran
|
||||
2003), ISO/IEC 1539-1:2010 (Fortran 2008), the Technical Specification
|
||||
@code{Further Interoperability of Fortran with C} (ISO/IEC TS 29113:2012).
|
||||
Full support of those standards and future Fortran standards is planned.
|
||||
The current status of the support is can be found in the
|
||||
@ref{Fortran 2003 status}, @ref{Fortran 2008 status} and
|
||||
@ref{TS 29113 status} sections of the documentation.
|
||||
|
||||
Additionally, the GNU Fortran compilers supports the OpenMP specification
|
||||
(version 3.1, @url{http://openmp.org/@/wp/@/openmp-specifications/}).
|
||||
|
|
@ -545,6 +546,10 @@ for them, which work with GNU Fortran. They can be found at
|
|||
@uref{http://www.fortran.com/@/iso_varying_string.f95} and at
|
||||
@uref{ftp://ftp.nag.co.uk/@/sc22wg5/@/ISO_VARYING_STRING/}.
|
||||
|
||||
Deferred-length character strings of Fortran 2003 supports part of
|
||||
the features of @code{ISO_VARYING_STRING} and should be considered as
|
||||
replacement. (Namely, allocatable or pointers of the type
|
||||
@code{character(len=:)}.)
|
||||
|
||||
|
||||
@c =====================================================================
|
||||
|
|
@ -807,8 +812,8 @@ operators bound to a type.
|
|||
override type-bound procedures or to have deferred binding.
|
||||
|
||||
@item Polymorphic entities (``@code{CLASS}'') for derived types -- including
|
||||
@code{SAME_TYPE_AS}, @code{EXTENDS_TYPE_OF} and @code{SELECT TYPE}.
|
||||
Note that unlimited polymorphism is currently not supported.
|
||||
@code{SAME_TYPE_AS}, @code{EXTENDS_TYPE_OF} and @code{SELECT TYPE} for
|
||||
scalars and arrays, including unlimited polymorphism.
|
||||
|
||||
@item Generic interface names, which have the same name as derived types,
|
||||
are now supported. This allows one to write constructor functions. Note
|
||||
|
|
@ -1079,16 +1084,23 @@ The @uref{http://gcc.gnu.org/wiki/TS29113Status, wiki} has some information
|
|||
about the current TS 29113 implementation status. In particular, the
|
||||
following is implemented.
|
||||
|
||||
See also @ref{Further Interoperability of Fortran with C}.
|
||||
|
||||
@itemize
|
||||
@item The @option{-std=f2008ts} option.
|
||||
|
||||
@item The @code{OPTIONAL} attribute is allowed for dummy arguments
|
||||
of @code{BIND(C) procedures.}
|
||||
|
||||
@item The RANK intrinsic is supported.
|
||||
@item The @code{RANK} intrinsic is supported.
|
||||
|
||||
@item GNU Fortran's implementation for variables with @code{ASYNCHRONOUS}
|
||||
attribute is compatible with TS 29113.
|
||||
|
||||
@item Assumed types (@code{TYPE(*)}.
|
||||
|
||||
@item Assumed-rank (@code{DIMENSION(..)}). However, the array descriptor
|
||||
of the TS is not yet supported.
|
||||
@end itemize
|
||||
|
||||
|
||||
|
|
@ -2264,7 +2276,7 @@ Derived types with the C binding attribute shall not have the @code{sequence}
|
|||
attribute, type parameters, the @code{extends} attribute, nor type-bound
|
||||
procedures. Every component must be of interoperable type and kind and may not
|
||||
have the @code{pointer} or @code{allocatable} attribute. The names of the
|
||||
variables are irrelevant for interoperability.
|
||||
components are irrelevant for interoperability.
|
||||
|
||||
As there exist no direct Fortran equivalents, neither unions nor structs
|
||||
with bit field or variable-length array members are interoperable.
|
||||
|
|
@ -2304,11 +2316,14 @@ be compatible with C. The dummy argument declaration is relatively
|
|||
straightforward. However, one needs to be careful because C uses
|
||||
call-by-value by default while Fortran behaves usually similar to
|
||||
call-by-reference. Furthermore, strings and pointers are handled
|
||||
differently. Note that only explicit size and assumed-size arrays are
|
||||
supported but not assumed-shape or allocatable arrays.
|
||||
differently. Note that in Fortran 2003 and 2008 only explicit size
|
||||
and assumed-size arrays are supported but not assumed-shape or
|
||||
deferred-shape (i.e. allocatable or pointer) arrays. However, those
|
||||
are allowed since the Technical Specification 29113, see
|
||||
@ref{Further Interoperability of Fortran with C}
|
||||
|
||||
To pass a variable by value, use the @code{VALUE} attribute.
|
||||
Thus the following C prototype
|
||||
Thus, the following C prototype
|
||||
|
||||
@smallexample
|
||||
@code{int func(int i, int *j)}
|
||||
|
|
@ -2401,6 +2416,11 @@ The intrinsic procedures are described in @ref{Intrinsic Procedures}.
|
|||
C pointers are represented in Fortran via the special opaque derived type
|
||||
@code{type(c_ptr)} (with private components). Thus one needs to
|
||||
use intrinsic conversion procedures to convert from or to C pointers.
|
||||
|
||||
For some applications, using an assumed type (@code{TYPE(*)}) can be an
|
||||
alternative to a C pointer; see
|
||||
@ref{Further Interoperability of Fortran with C}.
|
||||
|
||||
For example,
|
||||
|
||||
@smallexample
|
||||
|
|
@ -2546,17 +2566,76 @@ END MODULE m
|
|||
@node Further Interoperability of Fortran with C
|
||||
@subsection Further Interoperability of Fortran with C
|
||||
|
||||
Assumed-shape and allocatable arrays are passed using an array descriptor
|
||||
(dope vector). The internal structure of the array descriptor used
|
||||
by GNU Fortran is not yet documented and will change. There will also be
|
||||
a Technical Specification (TS 29113) which standardizes an interoperable
|
||||
array descriptor. Until then, you can use the Chasm Language
|
||||
The Technical Specification ISO/IEC TS 29113:2012 on further
|
||||
interoperability of Fortran with C extends the interoperability support
|
||||
of Fortran 2003 and Fortran 2008. Besides removing some restrictions
|
||||
and constraints, it adds assumed-type (@code{TYPE(*)}) and assumed-rank
|
||||
(@code{dimension}) variables and allows for interoperability of
|
||||
assumed-shape, assumed-rank and deferred-shape arrays, including
|
||||
allocatables and pointers.
|
||||
|
||||
Note: Currently, GNU Fortran does not support the array descriptor
|
||||
(dope vector) as specified in the Technical Specification, but uses
|
||||
an array descriptor with different fields. The Chasm Language
|
||||
Interoperability Tools, @url{http://chasm-interop.sourceforge.net/},
|
||||
which provide an interface to GNU Fortran's array descriptor.
|
||||
provide an interface to GNU Fortran's array descriptor.
|
||||
|
||||
GNU Fortran already supports the C-interoperable @code{OPTIONAL}
|
||||
attribute; for absent arguments, a @code{NULL} pointer is passed.
|
||||
The Technical Specification adds the following new features, which
|
||||
are supported by GNU Fortran:
|
||||
|
||||
@itemize @bullet
|
||||
|
||||
@item The @code{ASYNCHRONOUS} attribute has been clarified and
|
||||
extended to allow its use with asynchronous communication in
|
||||
user-provided libraries such as in implementations of the
|
||||
Message Passing Interface specification.
|
||||
|
||||
@item Many constraints have been relaxed, in particular for
|
||||
the @code{C_LOC} and @code{C_F_POINTER} intrinsics.
|
||||
|
||||
@item The @code{OPTIONAL} attribute is now allowed for dummy
|
||||
arguments; an absent argument matches a @code{NULL} pointer.
|
||||
|
||||
@item Assumed types (@code{TYPE(*)}) have been added, which may
|
||||
only be used for dummy arguments. They are unlimited polymorphic
|
||||
but contrary to @code{CLASS(*)} they do not contain any type
|
||||
information, similar to C's @code{void *} pointers. Expressions
|
||||
of any type and kind can be passed; thus, it can be used as
|
||||
replacement for @code{TYPE(C_PTR)}, avoiding the use of
|
||||
@code{C_LOC} in the caller.
|
||||
|
||||
Note, however, that @code{TYPE(*)} only accepts scalar arguments,
|
||||
unless the @code{DIMENSION} is explicitly specified. As
|
||||
@code{DIMENSION(*)} only supports array (including array elements) but
|
||||
no scalars, it is not a full replacement for @code{C_LOC}. On the
|
||||
other hand, assumed-type assumed-rank dummy arguments
|
||||
(@code{TYPE(*), DIMENSION(..)}) allow for both scalars and arrays, but
|
||||
require special code on the callee side to handle the array descriptor.
|
||||
|
||||
@item Assumed-shape arrays (@code{DIMENSION(..)}) as dummy argument
|
||||
allow that scalars and arrays of any rank can be passed as actual
|
||||
argument. As the Technical Specification does not provide for direct
|
||||
means to operate with them, they have to be used either from the C side
|
||||
or be converted using @code{C_LOC} and @code{C_F_POINTER} to scalars
|
||||
or arrays of a specific rank. The rank can be determined using the
|
||||
@code{RANK} intrinisic.
|
||||
@end itemize
|
||||
|
||||
|
||||
Currently unimplemented:
|
||||
|
||||
@itemize @bullet
|
||||
|
||||
@item GNU Fortran always uses an array descriptor, which does not
|
||||
match the one of the Technical Specification. The
|
||||
@code{ISO_Fortran_binding.h} header file and the C functions it
|
||||
specifies are not available.
|
||||
|
||||
@item Using assumed-shape, assumed-rank and deferred-shape arrays in
|
||||
@code{BIND(C)} procedures is not fully supported. In particular,
|
||||
C interoperable strings of other length than one are not supported
|
||||
as this requires the new array descriptor.
|
||||
@end itemize
|
||||
|
||||
|
||||
@node GNU Fortran Compiler Directives
|
||||
|
|
@ -3100,7 +3179,7 @@ Environment variable for filename for * IO-unit.
|
|||
Environment variable for temporary file directory.
|
||||
|
||||
@item
|
||||
Environment variable forcing standard output to be line buffered (unix).
|
||||
Environment variable forcing standard output to be line buffered (Unix).
|
||||
|
||||
@end itemize
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue