110 lines
5.4 KiB
Plaintext
110 lines
5.4 KiB
Plaintext
1998-08-11
|
|
|
|
This directory contains the libf2c library packaged for use with g77
|
|
to configure and build automatically (in principle!) as part of the
|
|
top-level configure and make steps. g77 names this library `libg2c'
|
|
to avoid conflicts with existing copies of `libf2c' on a system.
|
|
|
|
Some small changes have been made vis-a-vis the netlib distribution of
|
|
libf2c, which comes from <ftp:bell-labs.com/netlib/f2c/> and is maintained
|
|
(excellently) by David M. Gay <dmg@bell-labs.com>. See the Notice files
|
|
for copyright information. We usually try to get g77-specific changes
|
|
rolled back into the libf2c distribution.
|
|
|
|
Files that come directly from netlib are either maintained in the
|
|
libf2c directory under their original names or, if they are not pertinent
|
|
for g77's version of libf2c, under their original names with `.netlib'
|
|
appended. For example, permissions.netlib is a copy of f2c's top-level
|
|
`permissions' file in the netlib distribution. In this case, it applies
|
|
only to the relevant portions of the libF77/ and libI77/ directories; it
|
|
does not apply to the libU77/ directory, which is distributed under
|
|
different licensing arrangements. Similarly, the `makefile.netlib' files
|
|
in the libF77/ and libI77/ subdirectories are copies of the respective
|
|
`makefile' files in the netlib distribution, but are not used when
|
|
building g77's version of libf2c.
|
|
|
|
The README.netlib files in libF77/ and libI77/ thus might be
|
|
interesting, but should not be taken as guidelines for how to
|
|
configure and build libf2c in g77's distribution.
|
|
|
|
* Read permissions.netlib for licensing conditions that apply to
|
|
distributing programs containing portions of code in the libF77/ and
|
|
libI77/ subdirectories. Also read disclaimer.netlib.
|
|
|
|
* Read libU77/COPYING.LIB for licensing conditions that apply to
|
|
distributing programs containing portions of code in the libU77/
|
|
subdirectory.
|
|
|
|
Among the user-visible changes (choices) g77 makes in its version of libf2c:
|
|
|
|
- f2c.h configured to default to padding unformatted direct reads
|
|
(#define Pad_UDread), because that's the behavior most users
|
|
expect.
|
|
|
|
- f2c.h configured to default to outputting leading zeros before
|
|
decimal points in formatted and list-directed output, to be compatible
|
|
with many other compilers (#define WANT_LEAD_0). Either way is
|
|
standard-conforming, however, and you should try to avoid writing
|
|
code that assumes one format or another.
|
|
|
|
- dtime_() and etime_() are from Dave Love's libU77, not from
|
|
netlib's libF77.
|
|
|
|
- Routines that are intended to be called directly via user code
|
|
(as in `CALL EXIT', but not the support routines for `OPEN')
|
|
have been renamed from `<name>' to `G77_<name>_0'. This, in
|
|
combination with g77 recognizing these names as intrinsics and
|
|
calling them directly by those names, reduces the likelihood of
|
|
interface mismatches occurring due to use of compiler options
|
|
that change code generation, and permits use of these names as
|
|
both intrinsics and user-supplied routines in applications (as
|
|
required by the Fortran standards). f2cext.c contains "jacket"
|
|
routines named `<name>' that call `G77_<name>_0', to support
|
|
code that relies on calling the relevant routines as `EXTERNAL'
|
|
routines.
|
|
|
|
Note that the `_0' in the name denotes version 0 of the *interface*,
|
|
not the *implementation*, of a routine. The interface of a
|
|
given routine *must not change* -- instead, introduce a new copy
|
|
of the code, with an increment (e.g. `_1') suffix, having the
|
|
new interface. Whether the previous interface is maintained is
|
|
not as important as ensuring the routine implementing the new
|
|
interface is never successfully linked to a call in existing,
|
|
e.g. previously compiled, code that expects the old interface.
|
|
|
|
- Version.c in the subdirectories contains g77-specific version
|
|
information and a routine (per subdirectory) to print both the
|
|
netlib and g77 version information when called. The `g77 -v'
|
|
command is designed to trigger this, by compiling, linking, and
|
|
running a small program that calls the routines in sequence.
|
|
|
|
- libF77/main.c no longer contains the actual code to copy the
|
|
argc and argv values into globals or to set up the signal-handling
|
|
environment. These have been removed to libF77/setarg.c and
|
|
libF77/setsig.c, respectively. libF77/main.c contains procedure
|
|
calls to the new code in place of the code itself. This should
|
|
simplify linking executables with a main() function other than
|
|
that in libF77/main.c (such as one written by the user in C or
|
|
C++). See the g77 documentation for more information.
|
|
|
|
- Complex-arithmetic support routines in libF77/ take a different approach
|
|
to avoiding problems resulting from aliased input and output arguments,
|
|
which should avoid particularly unusual alias problems that netlib
|
|
libf2c might suffer from.
|
|
|
|
- libF77/signal_.c supports systems with 64-bit pointers and 32-bit
|
|
integers.
|
|
|
|
- I/O routines in libI77/ have code to detect attempts to do recursive
|
|
I/O more "directly", mainly to lead to a clearer diagnostic than
|
|
typically occurs under such conditions.
|
|
|
|
- Formatted-I/O routines in libI77/ have code to pretty-print a FORMAT
|
|
string when printing a fatal diagnostic involving formatted I/O.
|
|
|
|
- libI77/open.c supports a more robust, perhaps more secure, method
|
|
of naming temporary files on some systems.
|
|
|
|
- Some g77-specific handling of building under Microsoft operating
|
|
systems exists, mainly in libI77/.
|