Table of Contents
This setting provides detailed control over the warnings about supported
extensions to the Fortran 77 Standard that were not adopted as part of
the Fortran 90 Standard. Note that ftnchek does not support the full
Fortran 90 language. However, it does support some common extensions to
Fortran 77 that were prevalent before Fortran 90 was defined. Some of
these extensions became part of the Fortran 90 Standard, but others did
not. The -f90 setting warns only about the latter. That is, this flag
covers things that are neither legal Fortran 77 nor legal Fortran 90.
Therefore, the warnings controlled by this flag are basically a subset
of the warnings controlled by -f77 . There are a few cases, described below,
where the circumstances in which the warning is given are slightly different
for the two flags.
The list consists of keywords separated by commas
or colons. There are three special keywords: all to turn on all the warnings
about nonstandard extensions, none to turn them all off, and help to
print the list of all the keywords with a brief explanation of each. If
list is omitted, -f90 is equivalent to -f90=all , and -nof90 is equivalent
to -f90=none .
The following keywords have identical meanings for -f90 as
for -f77 . The reader is referred to the explanations under -f77 .
||double-complex ||param-noparen |
|backslash ||format-dollarsign ||pointer
|byte ||format-edit-descr ||quad-constant |
|d-comment ||name-dollarsign ||variable-format |
The keywords which differ somewhat from the corresponding -f77
keywords are as follows.
- This is the same as for -f77 except
for the intrinsic functions defined in MIL-STD 1753, which are all included
in Fortran 90, and so are not warned about. (See -intrinsic for a list.)
- This is the same as for -f77 except that no warnings are
given for the I/O keywords that are standard in Fortran 90.
- Although the Fortran 90 Standard allows lines longer than 72 characters
in free source form, the restriction still applies to fixed source form,
which is the only form accepted by ftnchek .
- This is the same
as for -f77 except for expressions mixing extended precision real with
complex data types, which are permitted in Fortran 90.
- This is similar to the corresponding -f77 warning, but applies the somewhat
looser restrictions on statement order of the Fortran 90 Standard. In
particular, Fortran 90 allows DATA statements and statement-function definitions
to be intermixed with specification statements.
- In Fortran
90, binary, octal, and hexadecimal constants of the form B'ddd' , O'ddd' ,
and Z'ddd' , respectively, are permitted. Here 'ddd' represents a string
of digits. ftnchek recognizes these forms, as well as a variant of the
form X'ddd' for a hexadecimal constant, and other variants in which the
base indicator B , O , Z , or X follows the digit string. These variants
were not adopted in Fortran 90, so only they are warned about when this
flag is turned on.
See also: -f77 , -f95 , -portability , -pretty , -wordsize