-@c Copyright (C) 2004, 2005, 2006, 2007
+@c Copyright (C) 2004, 2005, 2006, 2007, 2008
@c Free Software Foundation, Inc.
@c This is part of the GNU Fortran manual.
@c For copying conditions, see the file gfortran.texi.
-ffixed-line-length-@var{n} -ffixed-line-length-none @gol
-ffree-line-length-@var{n} -ffree-line-length-none @gol
-fdefault-double-8 -fdefault-integer-8 -fdefault-real-8 @gol
--fcray-pointer -fopenmp -frange-check -fno-backslash -fmodule-private}
+-fcray-pointer -fopenmp -fno-range-check -fbackslash -fmodule-private}
@item Error and Warning Options
@xref{Error and Warning Options,,Options to request or suppress errors
-fsecond-underscore @gol
-fbounds-check -fmax-stack-var-size=@var{n} @gol
-fpack-derived -frepack-arrays -fshort-enums -fexternal-blas @gol
--fblas-matmul-limit=@var{n}}
+-fblas-matmul-limit=@var{n} -frecursive -finit-local-zero @gol
+-finit-integer=@var{n} -finit-real=@var{<zero|inf|-inf|nan>} @gol
+-finit-logical=@var{<true|false>} -finit-character=@var{n}}
@end table
@menu
@cindex character set
Allow @samp{$} as a valid character in a symbol name.
-@item -fno-backslash
-@opindex @code{fno-backslash}
+@item -fbackslash
+@opindex @code{backslash}
@cindex backslash
@cindex escape characters
-Change the interpretation of backslashes in string literals from
-``C-style'' escape characters to a single backslash character.
+Change the interpretation of backslashes in string literals
+from a single backslash character to ``C-style'' escape characters.
+The following combinations are expanded \a, \b, \f, \n, \r, \t,
+\v, \\, and \0 to the ASCII characters alert, backspace, form feed,
+newline, carriage return, horizontal tab, vertical tab, backslash,
+and NUL, respectively. All other combinations of a character preceded
+by \ are unexpanded.
@item -fmodule-private
@opindex @code{fmodule-private}
@item -fmax-identifier-length=@var{n}
@opindex @code{fmax-identifier-length=}@var{n}
Specify the maximum allowed identifier length. Typical values are
-31 (Fortran 95) and 63 (Fortran 2003).
+31 (Fortran 95) and 63 (Fortran 2003 and Fortran 2008).
@item -fimplicit-none
@opindex @code{fimplicit-none}
@code{!$} conditional compilation sentinels in free form
and @code{c$}, @code{*$} and @code{!$} sentinels in fixed form,
and when linking arranges for the OpenMP runtime library to be linked
-in.
+in. The option @option{-fopenmp} implies @option{-frecursive}.
-@item -frange-check
+@item -fno-range-check
@opindex @code{frange-check}
-Enable range checking on results of simplification of constant
-expressions during compilation. For example, by default, GNU Fortran
-will give an overflow error at compile time when simplifying @code{a =
-EXP(1000)}. With @option{-fno-range-check}, no error will be given and
-the variable @code{a} will be assigned the value @code{+Infinity}.
+Disable range checking on results of simplification of constant
+expressions during compilation. For example, GNU Fortran will give
+an error at compile time when simplifying @code{a = 1. / 0}.
+With this option, no error will be given and @code{a} will be assigned
+the value @code{+Infinity}. If an expression evaluates to a value
+outside of the relevant range of [@code{-HUGE()}:@code{HUGE()}],
+then the expression will be replaced by @code{-Inf} or @code{+Inf}
+as appropriate.
Similarly, @code{DATA i/Z'FFFFFFFF'/} will result in an integer overflow
on most systems, but with @option{-fno-range-check} the value will
``wrap around'' and @code{i} will be initialized to @math{-1} instead.
@item -std=@var{std}
@opindex @code{std=}@var{std} option
Specify the standard to which the program is expected to conform, which
-may be one of @samp{f95}, @samp{f2003}, @samp{gnu}, or @samp{legacy}.
-The default value for @var{std} is @samp{gnu}, which specifies a
-superset of the Fortran 95 standard that includes all of the extensions
-supported by GNU Fortran, although warnings will be given for obsolete
-extensions not recommended for use in new code. The @samp{legacy} value
-is equivalent but without the warnings for obsolete extensions, and may
-be useful for old non-standard programs. The @samp{f95} and
-@samp{f2003} values specify strict conformance to the Fortran 95 and
-Fortran 2003 standards, respectively; errors are given for all
-extensions beyond the relevant language standard, and warnings are given
-for the Fortran 77 features that are permitted but obsolescent in later
-standards.
+may be one of @samp{f95}, @samp{f2003}, @samp{f2008}, @samp{gnu}, or
+@samp{legacy}. The default value for @var{std} is @samp{gnu}, which
+specifies a superset of the Fortran 95 standard that includes all of the
+extensions supported by GNU Fortran, although warnings will be given for
+obsolete extensions not recommended for use in new code. The
+@samp{legacy} value is equivalent but without the warnings for obsolete
+extensions, and may be useful for old non-standard programs. The
+@samp{f95}, @samp{f2003} and @samp{f2008} values specify strict
+conformance to the Fortran 95, Fortran 2003 and Fortran 2008 standards,
+respectively; errors are given for all extensions beyond the relevant
+language standard, and warnings are given for the Fortran 77 features
+that are permitted but obsolescent in later standards.
@end table
by GNU Fortran:
@table @gcctabopt
-@item -fmax-errors-@var{n}
-@opindex @code{fmax-errors-}@var{n}
+@item -fmax-errors=@var{n}
+@opindex @code{fmax-errors=}@var{n}
@cindex errors, limiting
Limits the maximum number of error messages to @var{n}, at which point
GNU Fortran bails out rather than attempting to continue processing the
nonstandard practices, but not all.
However, improvements to GNU Fortran in this area are welcome.
-This should be used in conjunction with @option{-std=f95} or
-@option{-std=f2003}.
+This should be used in conjunction with @option{-std=f95},
+@option{-std=f2003} or @option{-std=f2008}.
@item -pedantic-errors
@opindex @code{pedantic-errors}
@cindex warnings, ampersand
@cindex &
Warn about missing ampersand in continued character constants. The warning is
-given with @option{-Wampersand}, @option{-pedantic}, @option{-std=f95}, and
-@option{-std=f2003}. Note: With no ampersand given in a continued character
-constant, GNU Fortran assumes continuation at the first non-comment,
-non-whitespace character after the ampersand that initiated the continuation.
+given with @option{-Wampersand}, @option{-pedantic}, @option{-std=f95},
+@option{-std=f2003} and @option{-std=f2008}. Note: With no ampersand
+given in a continued character constant, GNU Fortran assumes continuation
+at the first non-comment, non-whitespace character after the ampersand
+that initiated the continuation.
@item -Wcharacter-truncation
@opindex @code{Wcharacter-truncation}
@cindex warnings, character truncation
Warn when a character assignment will truncate the assigned string.
+@item -Wline-truncation
+@opindex @code{Wline-truncation}
+@cindex warnings, line truncation
+Warn when a source code line will be truncated.
+
@item -Wconversion
@opindex @code{Wconversion}
@cindex warnings, conversion
@item
A LOGICAL SELECT construct has three CASE statements.
+
+@item
+A TRANSFER specifies a source that is shorter than the destination.
@end itemize
@item -Wtabs
@cindex warnings, tabs
@cindex tabulators
By default, tabs are accepted as whitespace, but tabs are not members
-of the Fortran Character Set. @option{-Wno-tabs} will cause a warning
-to be issued if a tab is encountered. Note, @option{-Wno-tabs} is active
-for @option{-pedantic}, @option{-std=f95}, @option{-std=f2003}, and
-@option{-Wall}.
+of the Fortran Character Set. For continuation lines, a tab followed
+by a digit between 1 and 9 is supported. @option{-Wno-tabs} will cause
+a warning to be issued if a tab is encountered. Note, @option{-Wno-tabs}
+is active for @option{-pedantic}, @option{-std=f95}, @option{-std=f2003},
+@option{-std=f2008} and @option{-Wall}.
@item -Wunderflow
@opindex @code{Wunderflow}
@samp{precision} (loss of precision during operation) and @samp{denormal}
(operation produced a denormal value).
+Some of the routines in the Fortran runtime library, like
+@samp{CPU_TIME}, are likely to to trigger floating point exceptions when
+@code{ffpe-trap=precision} is used. For this reason, the use of
+@code{ffpe-trap=precision} is not recommended.
+
@item -fbacktrace
@opindex @code{fbacktrace}
@cindex backtrace
@opindex @code{fno-automatic}
@cindex @code{SAVE} statement
@cindex statement, @code{SAVE}
-Treat each program unit as if the @code{SAVE} statement was specified for
-every local variable and array referenced in it. Does not affect common
-blocks. (Some Fortran compilers provide this option under the name
-@option{-static}.)
+Treat each program unit (except those marked as RECURSIVE) as if the
+@code{SAVE} statement were specified for every local variable and array
+referenced in it. Does not affect common blocks. (Some Fortran compilers
+provide this option under the name @option{-static} or @option{-save}.)
+The default, which is @option{-fautomatic}, uses the stack for local
+variables smaller than the value given by @option{-fmax-stack-var-size}.
+Use the option @option{-frecursive} to use no static memory.
@item -ff2c
@opindex ff2c
Use of @option{-fno-underscoring} is not recommended unless you are
experimenting with issues such as integration of GNU Fortran into
-existing system environments (vis-a-vis existing libraries, tools, and
-so on).
+existing system environments (vis-@`{a}-vis existing libraries, tools,
+and so on).
For example, with @option{-funderscoring}, and assuming other defaults like
@option{-fcase-lower} and that @code{j()} and @code{max_count()} are
shape arrays against the actual allocated bounds.
Some checks require that @option{-fbounds-check} is set for
-the compilation of the main probram.
+the compilation of the main program.
In the future this may also include other forms of checking, e.g., checking
substring references.
@item -fmax-stack-var-size=@var{n}
@opindex @code{fmax-stack-var-size}
This option specifies the size in bytes of the largest array that will be put
-on the stack.
+on the stack; if the size is exceeded static memory is used (except in
+procedures marked as RECURSIVE). Use the option @option{-frecursive} to
+allow for recursive procedures which do not have a RECURSIVE attribute or
+for parallel programs. Use @option{-fno-automatic} to never use the stack.
This option currently only affects local arrays declared with constant
bounds, and may not apply to all character variables.
The default value for @var{n} is 30.
+@item -frecursive
+@opindex @code{frecursive}
+Allow indirect recursion by forcing all local arrays to be allocated
+on the stack. This flag cannot be used together with
+@option{-fmax-stack-var-size=} or @option{-fno-automatic}.
+
+@item -finit-local-zero
+@item -finit-integer=@var{n}
+@item -finit-real=@var{<zero|inf|-inf|nan>}
+@item -finit-logical=@var{<true|false>}
+@item -finit-character=@var{n}
+@opindex @code{finit-local-zero}
+@opindex @code{finit-integer}
+@opindex @code{finit-real}
+@opindex @code{finit-logical}
+@opindex @code{finit-character}
+The @option{-finit-local-zero} option instructs the compiler to
+initialize local @code{INTEGER}, @code{REAL}, and @code{COMPLEX}
+variables to zero, @code{LOGICAL} variables to false, and
+@code{CHARACTER} variables to a string of null bytes. Finer-grained
+initialization options are provided by the
+@option{-finit-integer=@var{n}},
+@option{-finit-real=@var{<zero|inf|-inf|nan>}} (which also initializes
+the real and imaginary parts of local @code{COMPLEX} variables),
+@option{-finit-logical=@var{<true|false>}}, and
+@option{-finit-character=@var{n}} (where @var{n} is an ASCII character
+value) options. These options do not initialize components of derived
+type variables, nor do they initialize variables that appear in an
+@code{EQUIVALENCE} statement. (This limitation may be removed in
+future releases).
+
+Note that the @option{-finit-real=nan} option initializes @code{REAL}
+and @code{COMPLEX} variables with a quiet NaN.
@end table
@xref{Code Gen Options,,Options for Code Generation Conventions,
OSDN Git Service
