and the Info entries for @file{gcc}, @file{cpp}, @file{g77}, @file{as},
@file{ld}, @file{binutils} and @file{gdb}.
@c man end
+@c man begin BUGS
+For instructions on reporting bugs, see
+@w{@uref{http://gcc.gnu.org/bugs.html}}. Use of the @command{gccbug}
+script to report bugs is recommended.
+@c man end
+@c man begin AUTHOR
+See the Info entry for @file{gcc}, or
+@w{@uref{http://gcc.gnu.org/thanks.html}}, for contributors to GCC.
+@c man end
@end ignore
@node Invoking GCC
@cindex grouping options
@cindex options, grouping
-The @code{gcc} program accepts options and file names as operands. Many
+The @command{gcc} program accepts options and file names as operands. Many
options have multi-letter names; therefore multiple single-letter options
may @emph{not} be grouped: @samp{-dr} is very different from @w{@samp{-d
-r}}.
For any given input file, the file name suffix determines what kind of
compilation is done:
-@table @code
+@table @gcctabopt
@item @var{file}.c
C source code which must be preprocessed.
You can specify the input language explicitly with the @samp{-x} option:
-@table @code
+@table @gcctabopt
@item -x @var{language}
Specify explicitly the @var{language} for the following input files
(rather than letting the compiler choose a default based on the file
has not been used at all).
@item -pass-exit-codes
-Normally the @code{gcc} program will exit with the code of 1 if any
+Normally the @command{gcc} program will exit with the code of 1 if any
phase of the compiler returns a non-success return code. If you specify
-@samp{-pass-exit-codes}, the @code{gcc} program will instead return with
+@samp{-pass-exit-codes}, the @command{gcc} program will instead return with
numerically highest error produced by any phase that returned an error
indication.
@end table
If you only want some of the stages of compilation, you can use
-@samp{-x} (or filename suffixes) to tell @code{gcc} where to start, and
+@samp{-x} (or filename suffixes) to tell @command{gcc} where to start, and
one of the options @samp{-c}, @samp{-S}, or @samp{-E} to say where
-@code{gcc} is to stop. Note that some combinations (for example,
-@samp{-x cpp-output -E} instruct @code{gcc} to do nothing at all.
+@command{gcc} is to stop. Note that some combinations (for example,
+@samp{-x cpp-output -E}) instruct @command{gcc} to do nothing at all.
-@table @code
+@table @gcctabopt
@item -c
Compile or assemble the source files, but do not link. The linking
stage simply is not done. The ultimate output is in the form of an
@item --help
Print (on the standard output) a description of the command line options
-understood by @code{gcc}. If the @code{-v} option is also specified
-then @code{--help} will also be passed on to the various processes
-invoked by @code{gcc}, so that they can display the command line options
-they accept. If the @code{-W} option is also specified then command
+understood by @command{gcc}. If the @option{-v} option is also specified
+then @option{--help} will also be passed on to the various processes
+invoked by @command{gcc}, so that they can display the command line options
+they accept. If the @option{-W} option is also specified then command
line options which have no documentation associated with them will also
be displayed.
preprocessed C++ files use the suffix @samp{.ii}. GCC recognizes
files with these names and compiles them as C++ programs even if you
call the compiler the same way as for compiling C programs (usually with
-the name @code{gcc}).
+the name @command{gcc}).
@findex g++
@findex c++
compiler that understands the C++ language---and under some
circumstances, you might want to compile programs from standard input,
or otherwise without a suffix that flags them as C++ programs.
-@code{g++} is a program that calls GCC with the default language
+@command{g++} is a program that calls GCC with the default language
set to C++, and automatically specifies linking against the C++
-library. On many systems, @code{g++} is also
-installed with the name @code{c++}.
+library. On many systems, @command{g++} is also
+installed with the name @command{c++}.
-@cindex invoking @code{g++}
+@cindex invoking @command{g++}
When you compile C++ programs, you may specify many of the same
command-line options that you use for compiling programs in any
language; or command-line options meaningful for C and related
The following options control the dialect of C (or languages derived
from C, such as C++ and Objective C) that the compiler accepts:
-@table @code
+@table @gcctabopt
@cindex ANSI support
@cindex ISO support
@item -ansi
@table @samp
@item iso9899:1990
-Same as -ansi
+Same as @option{-ansi}
@item iso9899:199409
ISO C as modified in amend. 1
@item iso9899:1999
ISO C99. Note that this standard is not yet fully supported; see
-@uref{http://gcc.gnu.org/c99status.html} for more information.
+@w{@uref{http://gcc.gnu.org/c99status.html}} for more information.
@item c89
-same as -std=iso9899:1990
+same as @option{-std=iso9899:1990}
@item c99
-same as -std=iso9899:1999
+same as @option{-std=iso9899:1999}
@item gnu89
default, iso9899:1990 + gnu extensions
iso9899:1999 + gnu extensions
@item iso9899:199x
-same as -std=iso9899:1999, deprecated
+same as @option{-std=iso9899:1999}, deprecated
@item c9x
-same as -std=iso9899:1999, deprecated
+same as @option{-std=iso9899:1999}, deprecated
@item gnu9x
-same as -std=gnu99, deprecated
+same as @option{-std=gnu99}, deprecated
@end table
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 -std=c99 is not specified.
+when @option{-std=c99} is not specified.
@xref{Standards,,Language Standards Supported by GCC}, for details of
these standard versions.
Here is a list of options that are @emph{only} for compiling C++ programs:
-@table @code
+@table @gcctabopt
@item -fno-access-control
Turn off all access checking. This switch is mainly useful for working
around bugs in the access control code.
In addition, these optimization, warning, and code generation options
have meanings only for C++ programs:
-@table @code
+@table @gcctabopt
@item -fno-default-inline
Do not assume @samp{inline} for functions defined inside a class scope.
@xref{Optimize Options,,Options That Control Optimization}. Note that these
The following @samp{-W@dots{}} options are not affected by @samp{-Wall}.
-@table @code
+@table @gcctabopt
@item -Weffc++ (C++ only)
Warn about violations of various style guidelines from Scott Meyers'
@cite{Effective C++} books. If you use this option, you should be aware
honor these options. However it is expected, in the near future, that
the remaining front-ends would be able to digest them correctly.
-@table @code
+@table @gcctabopt
@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 for g++ and 0 for the rest of
These options control the amount and kinds of warnings produced by GCC:
-@table @code
+@table @gcctabopt
@cindex syntax checking
@item -fsyntax-only
Check the code for syntax errors, but don't do anything beyond that.
There is some controversy over the precise meaning of the sequence point
rules in subtle cases. Alternative formal definitions may be found in
Clive Feather's ``Annex S''
-@uref{http://wwwold.dkuug.dk/JTC1/SC22/WG14/www/docs/n925.htm} and in
+@w{@uref{http://wwwold.dkuug.dk/JTC1/SC22/WG14/www/docs/n925.htm}} and in
Michael Norrish's thesis
-@uref{http://www.cl.cam.ac.uk/users/mn200/PhD/thesis-report.ps.gz}.
+@w{@uref{http://www.cl.cam.ac.uk/users/mn200/PhD/thesis-report.ps.gz}}.
Other discussions are by Raymond Mak
-@uref{http://wwwold.dkuug.dk/JTC1/SC22/WG14/www/docs/n926.htm} and
+@w{@uref{http://wwwold.dkuug.dk/JTC1/SC22/WG14/www/docs/n926.htm}} and
D. Hugh Redelmeier
-@uref{http://wwwold.dkuug.dk/JTC1/SC22/WG14/www/docs/n927.htm}.
+@w{@uref{http://wwwold.dkuug.dk/JTC1/SC22/WG14/www/docs/n927.htm}}.
@item -Wreturn-type
Warn whenever a function is defined with a return-type that defaults to
in some cases, and there is no simple way to modify the code to suppress
the warning.
-@table @code
+@table @gcctabopt
@item -W
Print extra warning messages for these events:
GCC has various special options that are used for debugging
either your program or GCC:
-@table @code
+@table @gcctabopt
@item -g
Produce debugging information in the operating system's native format
(stabs, COFF, XCOFF, or DWARF). GDB can work with this debugging
@item __bb_trace__
Write the sequence of basic blocks executed to file @file{bbtrace.gz}.
The file will be compressed using the program @samp{gzip}, which must
-exist in your @code{PATH}. On systems without the @samp{popen}
+exist in your @env{PATH}. On systems without the @samp{popen}
function, the file will be named @file{bbtrace} and will not be
compressed. @strong{Profiling for even a few seconds on these systems
will produce a very large file.} Note: @code{__bb_hidecall__} and
(@pxref{Gcov,, @code{gcov}: a GCC Test Coverage Program}).
The data file names begin with the name of your source file:
-@table @code
+@table @gcctabopt
@item @var{sourcename}.bb
A mapping from basic blocks to line numbers, which @code{gcov} uses to
associate basic block execution counts with line numbers.
@samp{installation problem, cannot exec cpp0: No such file or directory}.
To resolve this you either need to put @file{cpp0} and the other compiler
components where gcc expects to find them, or you can set the environment
-variable @code{GCC_EXEC_PREFIX} to the directory where you installed them.
+variable @env{GCC_EXEC_PREFIX} to the directory where you installed them.
Don't forget the trailing '/'.
@xref{Environment Variables}.
@end table
These options control various sorts of optimizations:
-@table @code
+@table @gcctabopt
@item -O
@itemx -O1
Optimize. Optimizing compilation takes somewhat more time, and a lot
You can figure out the other form by either removing @samp{no-} or
adding it.
-@table @code
+@table @gcctabopt
@item -ffloat-store
Do not store floating point variables in registers, and inhibit other
options that might change whether a floating point value is taken from a
You can use the following flags in the rare cases when ``fine-tuning''
of optimizations to be performed is desired.
-@table @code
+@table @gcctabopt
@item -fstrength-reduce
Perform the optimizations of loop strength reduction and
elimination of iteration variables.
instructions. GCC enables this optimization by default with @samp{-O2}
or higher.
-Note @code{-fregmove} and @code{-foptimize-register-move} are the same
+Note @option{-fregmove} and @option{-foptimize-register-move} are the same
optimization.
@item -fdelayed-branch
they have helped determine the efficacy of various
approaches to improving loop optimizations.
-Please let us (@email{gcc@@gcc.gnu.org} and @email{fortran@@gnu.org})
+Please let us (@w{@email{gcc@@gcc.gnu.org}} and @w{@email{fortran@@gnu.org}})
know how use of these options affects
the performance of your production code.
We're very interested in code that runs @emph{slower}
@item -fbranch-probabilities
After running a program compiled with @samp{-fprofile-arcs}
(@pxref{Debugging Options,, Options for Debugging Your Program or
-@code{gcc}}), you can compile it a second time using
+@command{gcc}}), you can compile it a second time using
@samp{-fbranch-probabilities}, to improve optimizations based on
guessing the path a branch might take.
they cause the preprocessor output to be unsuitable for actual
compilation.
-@table @code
+@table @gcctabopt
@item -include @var{file}
Process @var{file} as input before processing the regular input file.
In effect, the contents of @var{file} are compiled first. Any @samp{-D}
the rules to stdout and suppresses normal preprocessed output.
Another way to specify output of a @code{make} rule is by setting
-the environment variable @code{DEPENDENCIES_OUTPUT} (@pxref{Environment
+the environment variable @env{DEPENDENCIES_OUTPUT} (@pxref{Environment
Variables}).
@item -MG
@c prevent bad page break with this line
You can pass options to the assembler.
-@table @code
+@table @gcctabopt
@item -Wa,@var{option}
Pass @var{option} as an option to the assembler. If @var{option}
contains commas, it is split into multiple options at the commas.
an executable output file. They are meaningless if the compiler is
not doing a link step.
-@table @code
+@table @gcctabopt
@cindex file names
@item @var{object-file-name}
A file name that does not end in a special recognized suffix is
@item -nostartfiles
Do not use the standard system startup files when linking.
-The standard system libraries are used normally, unless @code{-nostdlib}
-or @code{-nodefaultlibs} is used.
+The standard system libraries are used normally, unless @option{-nostdlib}
+or @option{-nodefaultlibs} is used.
@item -nodefaultlibs
Do not use the standard system libraries when linking.
Only the libraries you specify will be passed to the linker.
-The standard startup files are used normally, unless @code{-nostartfiles}
+The standard startup files are used normally, unless @option{-nostartfiles}
is used. The compiler may generate calls to memcmp, memset, and memcpy
for System V (and ISO C) environments or to bcopy and bzero for
BSD environments. These entries are usually resolved by entries in
or @samp{-nodefaultlibs} you should usually specify @samp{-lgcc} as well.
This ensures that you have no unresolved references to internal GCC
library subroutines. (For example, @samp{__main}, used to ensure C++
-constructors will be called; @pxref{Collect2,,@code{collect2}}.)
+constructors will be called; @pxref{Collect2,,@command{collect2}}.)
@item -s
Remove all symbol table and relocation information from the executable.
form an executable. Not all systems support this option. For predictable
results, you must also specify the same set of options that were used to
generate code (@samp{-fpic}, @samp{-fPIC}, or model suboptions)
-when you specify this option.@footnote{On some systems, @code{gcc -shared}
+when you specify this option.@footnote{On some systems, @samp{gcc -shared}
needs to build supplementary stub code for constructors to work. On
-multi-libbed systems, @code{gcc -shared} must select the correct support
+multi-libbed systems, @samp{gcc -shared} must select the correct support
libraries to link against. Failing to supply the correct flags may lead
to subtle defects. Supplying them in cases where they are not necessary
is innocuous.}
These options specify directories to search for header files, for
libraries and for parts of the compiler:
-@table @code
+@table @gcctabopt
@item -I@var{dir}
Add the directory @var{dir} to the head of the list of directories to be
searched for header files. This can be used to override a system header
@file{/usr/lib/gcc/} and @file{/usr/local/lib/gcc-lib/}. If neither of
those results in a file name that is found, the unmodified program
name is searched for using the directories specified in your
-@samp{PATH} environment variable.
+@env{PATH} environment variable.
@samp{-B} prefixes that effectively specify directory names also apply
to libraries in the linker, because the compiler translates these
out of the link if it is not found by those means.
Another way to specify a prefix much like the @samp{-B} prefix is to use
-the environment variable @code{GCC_EXEC_PREFIX}. @xref{Environment
+the environment variable @env{GCC_EXEC_PREFIX}. @xref{Environment
Variables}.
@item -specs=@var{file}
@node Spec Files
@section Specifying subprocesses and the switches to pass to them
@cindex Spec Files
-@code{GCC} is a driver program. It performs its job by invoking a
+@command{gcc} is a driver program. It performs its job by invoking a
sequence of other programs to do the work of compiling, assembling and
linking. GCC interprets its command-line parameters and uses these to
deduce which programs it should invoke, and which command-line options
@table @code
@item @@@var{language}
This says that the suffix is an alias for a known @var{language}. This is
-similar to using the @code{-x} command-line switch to GCC to specify a
+similar to using the @option{-x} command-line switch to GCC to specify a
language explicitly. For example:
@smallexample
by side. One of them (probably the newest) will be the default, but
you may sometimes wish to use another.
-@table @code
+@table @gcctabopt
@item -b @var{machine}
The argument @var{machine} specifies the target machine for compilation.
This is useful when you have installed GCC as a cross-compiler.
80386} becomes an alias for @samp{-b i386v}.
In one respect, the @samp{-b} or @samp{-V} do not completely change
-to a different compiler: the top-level driver program @code{gcc}
+to a different compiler: the top-level driver program @command{gcc}
that you originally invoked continues to run and invoke the other
executables (preprocessor, compiler per se, assembler and linker)
that do the real work. However, since no real work is done in the
install different instances of the driver program, compiled for
different targets or versions, under different names.
-For example, if the driver for version 2.0 is installed as @code{ogcc}
-and that for version 2.1 is installed as @code{gcc}, then the command
-@code{gcc} will use version 2.1 by default, while @code{ogcc} will use
+For example, if the driver for version 2.0 is installed as @command{ogcc}
+and that for version 2.1 is installed as @command{gcc}, then the command
+@command{gcc} will use version 2.1 by default, while @command{ogcc} will use
2.0 by default. However, you can choose either version with either
command with the @samp{-V} option.
the compiler was configured; the defaults for the most common choices are
given below.
-@table @code
+@table @gcctabopt
@item -m68000
@itemx -mc68000
Generate output for a 68000. This is the default
which style of microcontroller was selected when the compiler was configured;
the defaults for the most common choices are given below.
-@table @code
+@table @gcctabopt
@item -m6811
@itemx -m68hc11
Generate output for a 68HC11. This is the default
These @samp{-m} options are defined for the Vax:
-@table @code
+@table @gcctabopt
@item -munix
Do not output certain jump instructions (@code{aobleq} and so on)
that the Unix assembler for the Vax cannot handle across long
These @samp{-m} switches are supported on the SPARC:
-@table @code
+@table @gcctabopt
@item -mno-app-regs
@itemx -mapp-regs
Specify @samp{-mapp-regs} to generate output using the global registers
These @samp{-m} switches are supported in addition to the above
on the SPARCLET processor.
-@table @code
+@table @gcctabopt
@item -mlittle-endian
Generate code for a processor running in little-endian mode.
These @samp{-m} switches are supported in addition to the above
on SPARC V9 processors in 64 bit environments.
-@table @code
+@table @gcctabopt
@item -mlittle-endian
Generate code for a processor running in little-endian mode.
These @samp{-m} options are defined for Convex:
-@table @code
+@table @gcctabopt
@item -mc1
Generate output for C1. The code will run on any Convex machine.
The preprocessor symbol @code{__convex__c1__} is defined.
These @samp{-m} options are defined for the AMD Am29000:
-@table @code
+@table @gcctabopt
@item -mdw
@kindex -mdw
@cindex DW bit (29k)
These @samp{-m} options are defined for Advanced RISC Machines (ARM)
architectures:
-@table @code
+@table @gcctabopt
@item -mapcs-frame
@kindex -mapcs-frame
Generate a stack frame that is compliant with the ARM Procedure Call
@subsection Thumb Options
@cindex Thumb Options
-@table @code
+@table @gcctabopt
@item -mthumb-interwork
@kindex -mthumb-interwork
@subsection MN10200 Options
@cindex MN10200 options
These @samp{-m} options are defined for Matsushita MN10200 architectures:
-@table @code
+@table @gcctabopt
@item -mrelax
Indicate to the linker that it should perform a relaxation optimization pass
@cindex MN10300 options
These @samp{-m} options are defined for Matsushita MN10300 architectures:
-@table @code
+@table @gcctabopt
@item -mmult-bug
Generate code to avoid bugs in the multiply instructions for the MN10300
processors. This is the default.
These @samp{-m} options are defined for Mitsubishi M32R/D architectures:
-@table @code
+@table @gcctabopt
@item -mcode-model=small
Assume all objects live in the lower 16MB of memory (so that their addresses
can be loaded with the @code{ld24} instruction), and assume all subroutines
These @samp{-m} options are defined for Motorola 88k architectures:
-@table @code
+@table @gcctabopt
@item -m88000
@kindex -m88000
Generate code that works well on both the m88100 and the
@cindex IBM RS/6000 and PowerPC Options
These @samp{-m} options are defined for the IBM RS/6000 and PowerPC:
-@table @code
+@table @gcctabopt
@item -mpower
@itemx -mno-power
@itemx -mpower2
@itemx -mno-eabi
On System V.4 and embedded PowerPC systems do (do not) adhere to the
Embedded Applications Binary Interface (eabi) which is a set of
-modifications to the System V.4 specifications. Selecting @code{-meabi}
+modifications to the System V.4 specifications. Selecting @option{-meabi}
means that the stack is aligned to an 8 byte boundary, a function
@code{__eabi} is called to from @code{main} to set up the eabi
environment, and the @samp{-msdata} option can use both @code{r2} and
@code{r13} to point to two separate small data areas. Selecting
-@code{-mno-eabi} means that the stack is aligned to a 16 byte boundary,
+@option{-mno-eabi} means that the stack is aligned to a 16 byte boundary,
do not call an initialization function from @code{main}, and the
@samp{-msdata} option will only use @code{r13} to point to a single
small data area. The @samp{-meabi} option is on by default if you
These @samp{-m} options are defined for the IBM RT PC:
-@table @code
+@table @gcctabopt
@item -min-line-mul
Use an in-line code sequence for integer multiplies. This is the
default.
These @samp{-m} options are defined for the MIPS family of computers:
-@table @code
+@table @gcctabopt
@item -mcpu=@var{cpu type}
Assume the defaults for the machine type @var{cpu type} when scheduling
instructions. The choices for @var{cpu type} are @samp{r2000}, @samp{r3000},
These @samp{-m} options are defined for the i386 family of computers:
-@table @code
+@table @gcctabopt
@item -mcpu=@var{cpu type}
Assume the defaults for the machine type @var{cpu type} when scheduling
instructions. The choices for @var{cpu type} are @samp{i386},
These @samp{-m} options are defined for the HPPA family of computers:
-@table @code
+@table @gcctabopt
@item -march=@var{architecture type}
Generate code for the specified architecture. The choices for
@var{architecture type} are @samp{1.0} for PA 1.0, @samp{1.1} for PA
These @samp{-m} options are defined for the Intel 960 implementations:
-@table @code
+@table @gcctabopt
@item -m@var{cpu type}
Assume the defaults for the machine type @var{cpu type} for some of
the other options, including instruction scheduling, floating point
These @samp{-m} options are defined for the DEC Alpha implementations:
-@table @code
+@table @gcctabopt
@item -mno-soft-float
@itemx -msoft-float
Use (do not use) the hardware floating-point instructions for
-floating-point operations. When @code{-msoft-float} is specified,
+floating-point operations. When @option{-msoft-float} is specified,
functions in @file{libgcc1.c} will be used to perform floating-point
operations. Unless they are replaced by routines that emulate the
floating-point operations, or compiled in such a way as to call such
@item -mfp-reg
@itemx -mno-fp-regs
Generate code that uses (does not use) the floating-point register set.
-@code{-mno-fp-regs} implies @code{-msoft-float}. If the floating-point
+@option{-mno-fp-regs} implies @option{-msoft-float}. If the floating-point
register set is not used, floating point operands are passed in integer
registers as if they were integers and floating-point results are passed
in $0 instead of $f0. This is a non-standard calling sequence, so any
function with a floating-point argument or return value called by code
-compiled with @code{-mno-fp-regs} must also be compiled with that
+compiled with @option{-mno-fp-regs} must also be compiled with that
option.
A typical use of this option is building a kernel that does not use,
code is less efficient but is able to correctly support denormalized
numbers and exceptional IEEE values such as not-a-number and plus/minus
infinity. Other Alpha compilers call this option
-@code{-ieee_with_no_inexact}.
+@option{-ieee_with_no_inexact}.
@item -mieee-with-inexact
@c overfull hbox here --bob 22 jul96
These @samp{-m} options are defined for the Clipper implementations:
-@table @code
+@table @gcctabopt
@item -mc300
Produce code for a C300 Clipper processor. This is the default.
These @samp{-m} options are defined for the H8/300 implementations:
-@table @code
+@table @gcctabopt
@item -mrelax
Shorten some address references at link time, when possible; uses the
linker option @samp{-relax}. @xref{H8/300,, @code{ld} and the H8/300,
These @samp{-m} options are defined for the SH implementations:
-@table @code
+@table @gcctabopt
@item -m1
Generate code for the SH1.
@item -mnomacsave
Mark the @code{MAC} register as call-clobbered, even if
-@code{-mhitachi} is given.
+@option{-mhitachi} is given.
@item -misize
Dump instruction size and location in the assembly code.
which is incompatible with the SH ABI.
@item -mspace
-Optimize for space instead of speed. Implied by @code{-Os}.
+Optimize for space instead of speed. Implied by @option{-Os}.
@item -mprefergot
When generating position-independent code, emit function calls using
These additional options are available on System V Release 4 for
compatibility with other compilers on those systems:
-@table @code
+@table @gcctabopt
@item -G
Create a shared object.
It is recommended that @samp{-symbolic} or @samp{-shared} be used instead.
These @samp{-m} options are defined for TMS320C3x/C4x implementations:
-@table @code
+@table @gcctabopt
@item -mcpu=@var{cpu_type}
Set the instruction set, register set, and instruction scheduling
These @samp{-m} options are defined for V850 implementations:
-@table @code
+@table @gcctabopt
@item -mlong-calls
@itemx -mno-long-calls
Treat all calls as being far away (near). If calls are assumed to be
These options are defined for ARC implementations:
-@table @code
+@table @gcctabopt
@item -EL
Compile code for little endian mode. This is the default.
the compiler was configured; the defaults for the most common choices are
given below.
-@table @code
+@table @gcctabopt
@item -m32032
@itemx -m32032
Generate output for a 32032. This is the default
These options are defined for AVR implementations:
-@table @code
+@table @gcctabopt
@item -mmcu=@var{mcu}
Specify ATMEL AVR instruction set or MCU type.
These are the @samp{-m} options defined for the Motorola M*Core
processors.
-@table @code
+@table @gcctabopt
@item -mhardlit
@itemx -mhardlit
These @samp{-m} options are defined for D30V implementations:
-@table @code
+@table @gcctabopt
@item -mextmem
Link the @samp{.text}, @samp{.data}, @samp{.bss}, @samp{.strings},
@samp{.rodata}, @samp{.rodata1}, @samp{.data1} sections into external
can figure out the other form by either removing @samp{no-} or adding
it.
-@table @code
+@table @gcctabopt
@item -fexceptions
Enable exception handling. Generates extra code needed to propagate
exceptions. For some targets, this implies GNU CC will generate frame
use exception handling.
@item -funwind-tables
-Similar to @code{-fexceptions}, except that it will just generate any needed
+Similar to @option{-fexceptions}, except that it will just generate any needed
static data, but will not affect the generated code in any other way.
You will normally not enable this option; instead, a language processor
that needs this handling would enable it on your behalf.
destructors) in the form used by the GNU linker (on systems where the GNU
linker is the standard method of handling them). Use this option when
you want to use a non-GNU linker, which also requires using the
-@code{collect2} program to make sure the system linker includes
-constructors and destructors. (@code{collect2} is included in the GCC
-distribution.) For systems which @emph{must} use @code{collect2}, the
-compiler driver @code{gcc} is configured to do this automatically.
+@command{collect2} program to make sure the system linker includes
+constructors and destructors. (@command{collect2} is included in the GCC
+distribution.) For systems which @emph{must} use @command{collect2}, the
+compiler driver @command{gcc} is configured to do this automatically.
@item -finhibit-size-directive
Don't output a @code{.size} assembler directive, or anything else that
@xref{Driver}.
@end ifset
-@table @code
+@table @env
@item LANG
@itemx LC_CTYPE
@c @itemx LC_COLLATE
These environment variables control the way that GCC uses
localization information that allow GCC to work with different
national conventions. GCC inspects the locale categories
-@code{LC_CTYPE} and @code{LC_MESSAGES} if it has been configured to do
+@env{LC_CTYPE} and @env{LC_MESSAGES} if it has been configured to do
so. These locale categories can be set to any value supported by your
installation. A typical value is @samp{en_UK} for English in the United
Kingdom.
-The @code{LC_CTYPE} environment variable specifies character
+The @env{LC_CTYPE} environment variable specifies character
classification. GCC uses it to determine the character boundaries in
a string; this is needed for some multibyte encodings that contain quote
and escape characters that would otherwise be interpreted as a string
end or escape.
-The @code{LC_MESSAGES} environment variable specifies the language to
+The @env{LC_MESSAGES} environment variable specifies the language to
use in diagnostic messages.
-If the @code{LC_ALL} environment variable is set, it overrides the value
-of @code{LC_CTYPE} and @code{LC_MESSAGES}; otherwise, @code{LC_CTYPE}
-and @code{LC_MESSAGES} default to the value of the @code{LANG}
+If the @env{LC_ALL} environment variable is set, it overrides the value
+of @env{LC_CTYPE} and @env{LC_MESSAGES}; otherwise, @env{LC_CTYPE}
+and @env{LC_MESSAGES} default to the value of the @env{LANG}
environment variable. If none of these variables are set, GCC
defaults to traditional C English behavior.
@item TMPDIR
@findex TMPDIR
-If @code{TMPDIR} is set, it specifies the directory to use for temporary
+If @env{TMPDIR} is set, it specifies the directory to use for temporary
files. GCC uses temporary files to hold the output of one stage of
compilation which is to be used as input to the next stage: for example,
the output of the preprocessor, which is the input to the compiler
@item GCC_EXEC_PREFIX
@findex GCC_EXEC_PREFIX
-If @code{GCC_EXEC_PREFIX} is set, it specifies a prefix to use in the
+If @env{GCC_EXEC_PREFIX} is set, it specifies a prefix to use in the
names of the subprograms executed by the compiler. No slash is added
when this prefix is combined with the name of a subprogram, but you can
specify a prefix that ends with a slash if you wish.
-If @code{GCC_EXEC_PREFIX} is not set, GNU CC will attempt to figure out
+If @env{GCC_EXEC_PREFIX} is not set, GNU CC will attempt to figure out
an appropriate prefix to use based on the pathname it was invoked with.
If GCC cannot find the subprogram using the specified prefix, it
tries looking in the usual places for the subprogram.
-The default value of @code{GCC_EXEC_PREFIX} is
+The default value of @env{GCC_EXEC_PREFIX} is
@file{@var{prefix}/lib/gcc-lib/} where @var{prefix} is the value
of @code{prefix} when you ran the @file{configure} script.
In addition, the prefix is used in an unusual way in finding the
directories to search for header files. For each of the standard
directories whose name normally begins with @samp{/usr/local/lib/gcc-lib}
-(more precisely, with the value of @code{GCC_INCLUDE_DIR}), GCC tries
+(more precisely, with the value of @env{GCC_INCLUDE_DIR}), GCC tries
replacing that beginning with the specified prefix to produce an
alternate directory name. Thus, with @samp{-Bfoo/}, GCC will search
@file{foo/bar} where it would normally search @file{/usr/local/lib/bar}.
@item COMPILER_PATH
@findex COMPILER_PATH
-The value of @code{COMPILER_PATH} is a colon-separated list of
-directories, much like @code{PATH}. GCC tries the directories thus
+The value of @env{COMPILER_PATH} is a colon-separated list of
+directories, much like @env{PATH}. GCC tries the directories thus
specified when searching for subprograms, if it can't find the
-subprograms using @code{GCC_EXEC_PREFIX}.
+subprograms using @env{GCC_EXEC_PREFIX}.
@item LIBRARY_PATH
@findex LIBRARY_PATH
-The value of @code{LIBRARY_PATH} is a colon-separated list of
-directories, much like @code{PATH}. When configured as a native compiler,
+The value of @env{LIBRARY_PATH} is a colon-separated list of
+directories, much like @env{PATH}. When configured as a native compiler,
GCC tries the directories thus specified when searching for special
-linker files, if it can't find them using @code{GCC_EXEC_PREFIX}. Linking
+linker files, if it can't find them using @env{GCC_EXEC_PREFIX}. Linking
using GCC also uses these directories when searching for ordinary
libraries for the @samp{-l} option (but directories specified with
@samp{-L} come first).
@c @itemx OBJCPLUS_INCLUDE_PATH
These environment variables pertain to particular languages. Each
variable's value is a colon-separated list of directories, much like
-@code{PATH}. When GCC searches for header files, it tries the
+@env{PATH}. When GCC searches for header files, it tries the
directories listed in the variable for the language you are using, after
the directories specified with @samp{-I} but before the standard header
file directories.
(@pxref{Preprocessor Options}), but it goes to a separate file, and is
in addition to the usual results of compilation.
-The value of @code{DEPENDENCIES_OUTPUT} can be just a file name, in
+The value of @env{DEPENDENCIES_OUTPUT} can be just a file name, in
which case the Make rules are written to that file, guessing the target
name from the source file name. Or the value can have the form
@samp{@var{file} @var{target}}, in which case the rules are written to
which this information is used is to determine the character set to be used
when character literals, string literals and comments are parsed in C and C++.
When the compiler is configured to allow multibyte characters,
-the following values for @code{LANG} are recognized:
+the following values for @env{LANG} are recognized:
-@table @code
+@table @samp
@item C-JIS
Recognize JIS characters.
@item C-SJIS
Recognize EUCJP characters.
@end table
-If @code{LANG} is not defined, or if it has some other value, then the
+If @env{LANG} is not defined, or if it has some other value, then the
compiler will use mblen and mbtowc as defined by the default locale to
recognize and translate multibyte characters.
@end table
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