-@c Copyright (C) 1988, 89, 92-98, 1999 Free Software Foundation, Inc.
+@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
@item C Language Options
@xref{C Dialect Options,,Options Controlling C Dialect}.
@smallexample
--ansi -flang-isoc9x -fallow-single-precision -fcond-mismatch -fno-asm
+-ansi -fstd -fallow-single-precision -fcond-mismatch -fno-asm
-fno-builtin -ffreestanding -fhosted -fsigned-bitfields -fsigned-char
-funsigned-bitfields -funsigned-char -fwritable-strings
-traditional -traditional-cpp -trigraphs
-fhonor-std -fhuge-objects -fno-implicit-templates -finit-priority
-fno-implement-inlines -fname-mangling-version-@var{n} -fno-default-inline
-foperator-names -fno-optional-diags -fpermissive -frepo -fstrict-prototype
--fsquangle -ftemplate-depth-@var{n} -fvtable-thunks
+-fsquangle -ftemplate-depth-@var{n} -fuse-cxa-atexit -fvtable-thunks
-nostdinc++ -Wctor-dtor-privacy -Wno-deprecated -Weffc++
-Wno-non-template-friend
-Wnon-virtual-dtor -Wold-style-cast -Woverloaded-virtual
-mstructure-size-boundary=
-mbsd -mxopen -mno-symrename
-mabort-on-noreturn
+-mlong-calls -mno-long-calls
-mnop-fun-dllimport -mno-nop-fun-dllimport
-msingle-pic-base -mno-single-pic-base
-mpic-register=
-mpowerpc -mpowerpc64 -mno-powerpc
-mpowerpc-gpopt -mno-powerpc-gpopt
-mpowerpc-gfxopt -mno-powerpc-gfxopt
--mnew-mnemonics -mno-new-mnemonics
+-mnew-mnemonics -mold-mnemonics
-mfull-toc -mminimal-toc -mno-fop-in-toc -mno-sum-in-toc
-m64 -m32 -mxl-call -mno-xl-call -mthreads -mpe
-msoft-float -mhard-float -mmultiple -mno-multiple
-m4650 -msingle-float -mmad
-mstats -EL -EB -G @var{num} -nocpp
-mabi=32 -mabi=n32 -mabi=64 -mabi=eabi
--mno-crt0
+-mfix7000 -mno-crt0
@emph{i386 Options}
-mcpu=@var{cpu type}
-mreg-alloc=@var{list} -mregparm=@var{num}
-malign-jumps=@var{num} -malign-loops=@var{num}
-malign-functions=@var{num} -mpreferred-stack-boundary=@var{num}
+-mthreads -mno-align-stringops -minline-all-stringops
@emph{HPPA Options}
-march=@var{architecture type}
-m32032 -m32332 -m32532 -m32081 -m32381 -mmult-add -mnomult-add
-msoft-float -mrtd -mnortd -mregparam -mnoregparam -msb -mnosb
-mbitfield -mnobitfield -mhimem -mnohimem
+
+@emph{AVR Options}
+-mmcu=@var{mcu} -msize -minit-stack=@var{n} -mno-interrupts
+-mcall-prologues
+
+@emph{MCore Options}
+-mhardlit, -mno-hardlit -mdiv -mno-div -mrelax-immediates
+-mno-relax-immediates -mwide-bitfields -mno-wide-bitfields
+-m4byte-functions -mno-4byte-functions -mcallgraph-data
+-mno-callgraph-data -mslow-bytes -mno-slow-bytes -mno-lsim
+-mlittle-endian -mbig-endian -m210 -m340 -mstack-increment
@end smallexample
@item Code Generation Options
The functions @code{alloca}, @code{abort}, @code{exit}, and
@code{_exit} are not builtin functions when @samp{-ansi} is used.
-@item -flang-isoc9x
-Enable support for features found in the C9X standard. In particular,
-enable support for the C9X @code{restrict} keyword.
+@item -fstd=
+Determine the language standard. A value for this option must be provided;
+possible values are
+
+@itemize @minus
+@item iso9899:1990
+Same as -ansi
+
+@item iso9899:199409
+ISO C as modified in amend. 1
+
+@item iso9899:199x
+ISO C 9x
+
+@item c89
+same as -std=iso9899:1990
-Even when this option is not specified, you can still use some C9X
-features in so far as they do not conflict with previous C standards.
-For example, you may use @code{__restrict__} even when -flang-isoc9x
-is not specified.
+@item c9x
+same as -std=iso9899:199x
+
+@item gnu89
+default, iso9899:1990 + gnu extensions
+
+@item gnu9x
+iso9899:199x + gnu extensions
+@end itemize
+
+Even when this option is not specified, you can still use some of the
+features of newer standards in so far as they do not conflict with
+previous C standards. For example, you may use @code{__restrict__} even
+when -fstd=c9x is not specified.
@item -fno-asm
Do not recognize @code{asm}, @code{inline} or @code{typeof} as a
Specifying this option disables that optimization, and forces g++ to
call the copy constructor in all cases.
+@item -fno-enforce-eh-specs
+Don't check for violation of exception specifications at runtime. This
+option violates the C++ standard, but may be useful for reducing code
+size in production builds, much like defining @samp{NDEBUG}. The compiler
+will still optimize based on the exception specifications.
+
@item -fexternal-templates
Cause template instantiations to obey @samp{#pragma interface} and
@samp{implementation}; template instances are emitted or not according
Like all options that change the ABI, all C++ code, @emph{including
libgcc} must be built with the same setting of this option.
+@item -fmessage-length=@var{n}
+Try to format error messages so that they fit on lines of about @var{n}
+characters. The default is 72 characters. If @var{n} is zero, then no
+line-wrapping will be done; each error message will appear on a single
+line.
+
@item -fno-implicit-templates
Never emit code for non-inline templates which are instantiated
implicitly (i.e. by use); only emit code for explicit instantiations.
endless recursions during template class instantiation. ANSI/ISO C++
conforming programs must not rely on a maximum depth greater than 17.
+@item -fuse-cxa-atexit
+Register destructors for objects with static storage duration with the
+@code{__cxa_atexit} function rather than the @code{atexit} function.
+This option is required for fully standards-compliant handling of static
+destructors, but will only work if your C library supports
+@code{__cxa_atexit}.
+
@item -fvtable-thunks
Use @samp{thunks} to implement the virtual function dispatch table
(@samp{vtable}). The traditional (cfront-style) approach to
@item -Wfloat-equal
Warn if floating point values are used in equality comparisons.
+The idea behind this is that sometimes it is convenient (for the
+programmer) to consider floating-point values as approximations to
+infinitely precise real numbers. If you are doing this, then you need
+to compute (by analysing the code, or in some other way) the maximum or
+likely maximum error that the computation introduces, and allow for it
+when performing comparisons (and when producing output, but that's a
+different problem). In particular, instead of testing for equality, you
+would check to see whether the two values have ranges that overlap; and
+this is done with the relational operators, so equality comparisons are
+probably mistaken.
+
@item -Wtraditional (C only)
Warn about certain constructs that behave differently in traditional and
ANSI C.
signedness from its traditional type. This warning is only issued if
the base of the constant is ten. I.e. hexadecimal or octal values, which
typically represent bit patterns, are not warned about.
+
+@item
+Usage of ANSI string concatenation is detected.
@end itemize
@item -Wundef
* V850 Options::
* ARC Options::
* NS32K Options::
+* AVR Options::
+* MCore Options::
@end menu
@node M680x0 Options
Generate a call to the function abort at the end of a noreturn function.
It will be executed if the function tries to return.
+@item -mlong-calls
+@itemx -mno-long-calls
+Tells the compiler to perform function calls by first loading the
+address of the function into a register and then performing a subroutine
+call on this register. This switch is needed if the target function
+will lie outside of the 64 megabyte addressing range of the offset based
+version of subroutine call instruction.
+
+Even if this switch is enabled, not all function calls will be turned
+into long calls. The heuristic is that static functions, functions
+which have the @samp{short-call} attribute, functions that are inside
+the scope of a @samp{#pragma no_long_calls} directive and functions whose
+definitions have already been compiled within the current compilation
+unit, will not be turned into long calls. The exception to this rule is
+that weak function defintions, functions with the @samp{long-call}
+attribute or the @samp{section} attribute, and functions that are within
+the scope of a @samp{#pragma long_calls} directive, will always be
+turned into long calls.
+
+This feature is not enabled by default. Specifying
+@samp{--no-long-calls} will restore the default behaviour, as will
+placing the function calls within the scope of a @samp{#pragma
+long_calls_off} directive. Note these switches have no effect on how
+the compiler generates code to handle function calls via function
+pointers.
+
@item -mnop-fun-dllimport
@kindex -mnop-fun-dllimport
Disable the support for the @emph{dllimport} attribute.
Tell the MIPS assembler to not run its preprocessor over user
assembler files (with a @samp{.s} suffix) when assembling them.
+@item -mfix7000
+Pass an option to gas which will cause nops to be inserted if
+the read of the destination register of an mfhi or mflo instruction
+occurs in the following two instructions.
+
@item -no-crt0
Do not include the default crt0.
@end table
to stack space usage, such as embedded systems and operating system kernels,
may want to reduce the preferred alignment to
@samp{-mpreferred-stack-boundary=2}.
+
+@item -mthreads
+@kindex -mthreads
+Support thread-safe exception handling on @samp{Mingw32}. Code that relies
+on thread-safe exception handling must compile and link all code with the
+@samp{-mthreads} option. When compiling, @samp{-mthreads} defines
+@samp{-D_MT}; when linking, it links in a special thread helper library
+@samp{-lmingwthrd} which cleans up per thread exception handling data.
+
+@item -mno-align-stringops
+@kindex -mno-align-stringops
+Do not align destination of inlined string operations. This switch reduces
+code size and improves performance in case the destination is already aligned,
+but gcc don't know about it.
+
+@item -minline-all-stringops
+@kindex -minline-all-stringops
+By default GCC inlines string operations only when destination is known to be
+aligned at least to 4 byte boundary. This enables more inlining, increase code
+size, but may improve performance of code that depends on fast memcpy, strlen
+and memset for short lengths.
@end table
@node HPPA Options
@end table
+@node AVR Options
+@subsection AVR Options
+@cindex AVR Options
+
+These options are defined for AVR implementations:
+
+@table @code
+@item -mmcu=@var{mcu}
+Specify ATMEL AVR mcu (at90s23xx,attiny22,at90s44xx,at90s85xx,atmega603,
+atmega103).
+
+@item -msize
+Output instruction size's to the asm file
+
+@item -minit-stack=@var{N}
+Specify the initial stack address
+
+@item -mno-interrupts
+Generated code is not compatible with hardware interrupts.
+Code size will be smaller.
+
+@item -mcall-prologues
+Functions prologues/epilogues expanded as call to appropriate
+subroutines. Code size will be smaller.
+@end table
+
+@node MCore Options
+@subsection MCore Options
+@cindex MCore options
+
+These are the @samp{-m} options defined for the Motorola M*Core
+processors.
+
+@table @code
+
+@item -mhardlit
+@itemx -mhardlit
+@itemx -mno-hardlit
+Inline constants into the code stream if it can be done in two
+instructions or less.
+
+@item -mdiv
+@itemx -mdiv
+@itemx -mno-div
+Use the divide instruction. (Enabled by default).
+
+@item -mrelax-immediate
+@itemx -mrelax-immediate
+@itemx -mno-relax-immediate
+Allow arbitary sized immediated in bit operations.
+
+@item -mwide-bitfields
+@itemx -mwide-bitfields
+@itemx -mno-wide-bitfields
+Always treat bitfields as int-sized.
+
+@item -m4byte-functions
+@itemx -m4byte-functions
+@itemx -mno-4byte-functions
+Force all functions to be aligfned to a four byte boundary.
+
+@item -mcallgraph-data
+@itemx -mcallgraph-data
+@itemx -mno-callgraph-data
+Emit callgraph information.
+
+@item -mslow-bytes
+@itemx -mslow-bytes
+@itemx -mno-slow-bytes
+Prefer word access when reading byte quantities.
+
+@item -mlittle-endian
+@itemx -mlittle-endian
+@itemx -mbig-endian
+Genreate code for a little endian target.
+
+@item -m210
+@itemx -m210
+@itemx -m340
+Generate code for the 210 processor.
+
+@end table
@node Code Gen Options
The output from @code{protoize} or @code{unprotoize} replaces the
original source file. The original file is renamed to a name ending
-with @samp{.save}. If the @samp{.save} file already exists, then
-the source file is simply discarded.
+with @samp{.save} (for DOS, the saved filename ends in @samp{.sav}
+without the original @samp{.c} suffix). If the @samp{.save} (@samp{.sav}
+for DOS) file already exists, then the source file is simply discarded.
@code{protoize} and @code{unprotoize} both depend on GCC itself to
scan the program and collect information about the functions it uses.
the @var{compilation-options}, they are ignored.
@item -C
-Rename files to end in @samp{.C} instead of @samp{.c}.
-This is convenient if you are converting a C program to C++.
-This option applies only to @code{protoize}.
+Rename files to end in @samp{.C} (@samp{.cc} for DOS-based file
+systems) instead of @samp{.c}. This is convenient if you are converting
+a C program to C++. This option applies only to @code{protoize}.
@item -g
Add explicit global declarations. This means inserting explicit
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