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GCC(1)                  Version 1.40(28 November 1990)                   GCC(1)


NAME
      gcc - GNU project C Compiler

SYNOPSIS
      gcc [ options ] files

WARNING
      This man page is an extract of the documentation of the GNU C compiler
      and is limited to the meaning of the options.  It is not kept up to If
      you want to be certain of the information below, check it in the manual
      "Using and Porting GCC".  Refer to the Info file gcc.info or the DVI file
      gcc.dvi which are made from the Texinfo source file gcc.texinfo.

DESCRIPTION
      The GNU C compiler uses a command syntax much like the Unix C compiler.
      The gcc program accepts options and file names as operands.  Multiple
      single-letter options may not be grouped:  -dr is very different from -d
      -r.

      When you invoke GNU CC, it normally does preprocessing, compilation,
      assembly and linking.  File names which end in .c are taken as C source
      to be preprocessed and compiled; file names ending in .i are taken as
      preprocessor output to be compiled; compiler output files plus any input
      files with names ending in .s are assembled; then the resulting object
      files, plus any other input files, are linked together to produce an
      executable.

      Command options allow you to stop this process at an intermediate stage.
      For example, the -c option says not to run the linker.  Then the output
      consists of object files output by the assembler.

      Other command options are passed on to one stage of processing.  Some
      options control the preprocessor and others the compiler itself.  Yet
      other options control the assembler and linker; these are not documented
      here, but you rarely need to use any of them.

OPTIONS
      Here are the options to control the overall compilation process,
      including those that say whether to link, whether to assemble, and so on.

      -o file
            Place output in file file.  This applies regardless to whatever
            sort of output is being produced, whether it be an executable file,
            an object file, an assembler file or preprocessed C code.

            If -o is not specified, the default is to put an executable file in
            a.out, the object file source.c in source.o, an assembler file in
            source.s, and preprocessed C on standard output.

      -c    Compile or assemble the source files, but do not link.  Produce
            object files with names made by replacing .c or .s with .o at the
            end of the input file names.  Do nothing at all for object files


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            specified as input.

      -S    Compile into assembler code but do not assemble.  The assembler
            output file name is made by replacing .c with .s at the end of the
            input file name.  Do nothing at all for assembler source files or
            object files specified as input.

      -E    Run only the C preprocessor.  Preprocess all the C source files
            specified and output the results to standard output.

      -v    Compiler driver program prints the commands it executes as it runs
            the preprocessor, compiler proper, assembler and linker.  Some of
            these are directed to print their own version numbers.

      -pipe Use pipes rather than temporary files for communication between the
            various stages of compilation.  This fails to work on some systems
            where the assembler is unable to read from a pipe; but the GNU
            assembler has no trouble.

      -Bprefix
            Compiler driver program tries prefix as a prefix for each program
            it tries to run.  These programs are cpp, cc1, as and ld.

            For each subprogram to be run, the compiler driver first tries the
            -B prefix, if any.  If that name is not found, or if -B was not
            specified, the driver tries two standard prefixes, which are
            /usr/lib/gcc- and /usr/local/lib/gcc-.  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 PATH
            environment variable.

            The run-time support file gnulib is also searched for using the -B
            prefix, if needed.  If it is not found there, the two standard
            prefixes above are tried, and that is all.  The file is left out of
            the link if it is not found by those means.  Most of the time, on
            most machines, you can do without it.

            You can get a similar result from the environment variable
            GCCEXECPREFIX; if it is defined, its value is used as a prefix in
            the same way.  If both the -B option and the GCCEXECPREFIX
            variable are present, the -B option is used first and the
            environment variable value second.

      -bprefix
            The argument prefix is used as a second prefix for the compiler
            executables and libraries.  This prefix is optional: the compiler
            tries each file first with it, then without it.  This prefix
            follows the prefix specified with -B or the default prefixes.

            Thus, -bvax- -Bcc/ in the presence of environment variable
            GCCEXECPREFIX with definition /u/foo/ causes GNU CC to try the
            following file names for the preprocessor executable:


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GCC(1)                  Version 1.40(28 November 1990)                   GCC(1)


                  cc/vax-cpp
                  cc/cpp
                  /u/foo/vax-cpp
                  /u/foo/cpp
                  /usr/local/lib/gcc-vax-cpp
                  /usr/local/lib/gcc-cpp
                  /usr/lib/gcc-vax-cpp
                  /usr/lib/gcc-cpp

      These options control the details of C compilation itself.

      -ansi Support all ANSI standard C programs.

            This turns off certain features of GNU C that are incompatible with
            ANSI C, such as the asm, inline and typeof keywords, and predefined
            macros such as unix and vax that identify the type of system you
            are using.  It also enables the undesirable and rarely used ANSI
            trigraph feature.

            The alternate keywords asm, inline and typeof continue
            to work despite -ansi.  You would not want to use them in an ANSI C
            program, of course, but it useful to put them in header files that
            might be included in compilations done with -ansi.  Alternate
            predefined macros such as unix and vax are also available,
            with or without -ansi.

            The -ansi option does not cause non-ANSI programs to be rejected
            gratuitously.  For that, -pedantic is required in addition to
            -ansi.

            The macro STRICTANSI is predefined when the -ansi option is
            used.  Some header files may notice this macro and refrain from
            declaring certain functions or defining certain macros that the
            ANSI standard doesn't call for; this is to avoid interfering with
            any programs that might use these names for other things.

      -traditional
            Attempt to support some aspects of traditional C compilers.
            Specifically:

          * All extern declarations take effect globally even if they are
            written inside of a function definition.  This includes implicit
            declarations of functions.

          * The keywords typeof, inline, signed, const and volatile are not
            recognized.

          * Comparisons between pointers and integers are always allowed.

          * Integer types unsigned short and unsigned char promote to unsigned
            int.



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          * Out-of-range floating point literals are not an error.

          * All automatic variables not declared register are preserved by
            longjmp(3C).  Ordinarily, GNU C follows ANSI C: automatic variables
            not declared volatile may be clobbered.

          * In the preprocessor, comments convert to nothing at all, rather
            than to a space.  This allows traditional token concatenation.

          * In the preprocessor, macro arguments are recognized within string
            constants in a macro definition (and their values are stringified,
            though without additional quote marks, when they appear in such a
            context).  The preprocessor always considers a string constant to
            end at a newline.

          * The predefined macro STDC is not defined when you use
            -traditional, but GNUC is (since the GNU extensions which
            GNUC indicates are not affected by -traditional).  If you need
            to write header files that work differently depending on whether
            -traditional is in use, by testing both of these predefined macros
            you can distinguish four situations: GNU C, traditional GNU C,
            other ANSI C compilers, and other old C compilers.

      -O    Optimize.  Optimizing compilation takes somewhat more time, and a
            lot more memory for a large function.

            Without -O, the compiler's goal is to reduce the cost of
            compilation and to make debugging produce the expected results.
            Statements are independent: if you stop the program with a
            breakpoint between statements, you can then assign a new value to
            any variable or change the program counter to any other statement
            in the function and get exactly the results you would expect from
            the source code.

            Without -O, only variables declared register are allocated in
            registers.  The resulting compiled code is a little worse than
            produced by PCC without -O.

            With -O, the compiler tries to reduce code size and execution time.

            Some of the -f options described below turn specific kinds of
            optimization on or off.

      -g    Produce debugging information in the operating system's native
            format (for DBX or SDB).  GDB also can work with this debugging
            information.

            Unlike most other C compilers, GNU CC allows you to use -g with -O.
            The shortcuts taken by optimized code may occasionally produce
            surprising results: some variables you declared may not exist at
            all; flow of control may briefly move where you did not expect it;
            some statements may not be executed because they compute constant


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            results or their values were already at hand; some statements may
            execute in different places because they were moved out of loops.
            Nevertheless it proves possible to debug optimized output.  This
            makes it reasonable to use the optimizer for programs that might
            have bugs.

      -w    Inhibit all warning messages.

      -W    Print extra warning messages for these events:

          * An automatic variable is used without first being initialized.

            These warnings are possible only in optimizing compilation, because
            they require data flow information that is computed only when
            optimizing.  If you don't specify -O, you simply won't get these
            warnings.

            These warnings occur only for variables that are candidates for
            register allocation.  Therefore, they do not occur for a variable
            that is declared volatile, or whose address is taken, or whose size
            is other than 1, 2, 4 or 8 bytes.  Also, they do not occur for
            structures, unions or arrays, even when they are in registers.

            Note that there may be no warning about a variable that is used
            only to compute a value that itself is never used, because such
            computations may be deleted by data flow analysis before the
            warnings are printed.

            These warnings are made optional because GNU CC is not smart enough
            to see all the reasons why the code might be correct despite
            appearing to have an error.  Here is one example of how this can
            happen:

                  {
                    int x;
                    switch (y)
                      {
                      case 1: x = 1;
                        break;
                      case 2: x = 4;
                        break;
                      case 3: x = 5;
                      }
                    foo (x);
                  }

            If the value of y is always 1, 2 or 3, then x is always
            initialized, but GNU CC doesn't know this.  Here is another common
            case:

                  {
                    int save_y;


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                    if (change_y) save_y = y, y = new_y;
                    ...
                    if (change_y) y = save_y;
                  }

            This has no bug because save_y is used only if it is set.

            Some spurious warnings can be avoided if you declare as volatile
            all the functions you use that never return.

          * A nonvolatile automatic variable might be changed by a call to
            longjmp(3C).  These warnings as well are possible only in
            optimizing compilation.

            The compiler sees only the calls to setjmp(3C).  It cannot know
            where longjmp(3C) will be called; in fact, a signal handler could
            call it at any point in the code.  As a result, you may get a
            warning even when there is in fact no problem because longjmp(3C)
            cannot in fact be called at the place which would cause a problem.

          * A function can return either with or without a value.  (Falling off
            the end of the function body is considered returning without a
            value.)  For example, this function would evoke such a warning:

                  foo (a)
                  {
                    if (a > 0)
                      return a;
                  }

            Spurious warnings can occur because GNU CC does not realize that
            certain functions (including abort(3C) and longjmp(3C)) will never
            return.

          * An expression-statement contains no side effects.

            In the future, other useful warnings may also be enabled by this
            option.

      -Wimplicit
            Warn whenever a function is implicitly declared.

      -Wreturn-type
            Warn whenever a function is defined with a return-type that
            defaults to int.  Also warn about any return statement with no
            return-value in a function whose return-type is not void.

      -Wunused
            Warn whenever a local variable is unused aside from its
            declaration, and whenever a function is declared static but never
            defined.



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      -Wswitch
            Warn whenever a switch statement has an index of enumeral type and
            lacks a case for one or more of the named codes of that
            enumeration.  (The presence of a default label prevents this
            warning.)  case labels outside the enumeration range also provoke
            warnings when this option is used.

      -Wcomment
            Warn whenever a comment-start sequence /* appears in a comment.

      -Wtrigraphs
            Warn if any trigraphs are encountered (assuming they are enabled).

      -Wall All of the above -W options combined.  These are all the options
            which pertain to usage that we do not recommend and that we believe
            is always easy to avoid, even in conjunction with macros.

            The other -W...  options below are not implied by -Wall because
            certain kinds of useful macros are almost impossible to write
            without causing those warnings.

      -Wshadow
            Warn whenever a local variable shadows another local variable.

      -Wid-clash-len
            Warn whenever two distinct identifiers match in the first len
            characters.  This may help you prepare a program that will compile
            with certain obsolete, brain-damaged compilers.

      -Wpointer-arith
            Warn about anything that depends on the size of a function type or
            of void.  GNU C assigns these types a size of 1, for convenience in
            calculations with void * pointers and pointers to functions.

      -Wcast-qual
            Warn whenever a pointer is cast so as to remove a type qualifier
            from the target type.  For example, warn if a const char * is cast
            to an ordinary char *.

      -Wwrite-strings
            Give string constants the type const char[length] so that copying
            the address of one into a non-const char * pointer will get a
            warning.  These warnings will help you find at compile time code
            that can try to write into a string constant, but only if you have
            been very careful about using const in declarations and prototypes.
            Otherwise, it will just be a nuisance; this is why we did not make
            -Wall request these warnings.

      -p    Generate extra code to write profile information suitable for the
            analysis program prof(1).




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      -pg   Generate extra code to write profile information suitable for the
            analysis program gprof(1).

      -a    Generate extra code to write profile information for basic blocks,
            suitable for the analysis program tcov(1).  Eventually GNU gprof(1)
            should be extended to process this data.

      -llibrary
            Search a standard list of directories for a library named library,
            which is actually a file named liblibrary.a.  The linker uses this
            file as if it had been specified precisely by name.

            The directories searched include several standard system
            directories plus any that you specify with -L.

            Normally the files found this way are library files--archive files
            whose members are object files.  The linker handles an archive file
            by scanning through it for members which define symbols that have
            so far been referenced but not defined.  But if the file that is
            found is an ordinary object file, it is linked in the usual
            fashion.  The only difference between using an -l option and
            specifying a file name is that -l searches several directories.

      -Ldir Add directory dir to the list of directories to be searched for -l.

      -nostdlib
            Don't use the standard system libraries and startup files when
            linking.  Only the files you specify (plus gnulib) will be passed
            to the linker.

      -mmachinespec
            Machine-dependent option specifying something about the type of
            target machine.  These options are defined by the macro
            TARGETSWITCHES in the machine description.  The default for the
            options is also defined by that macro, which enables you to change
            the defaults.

            These are the -m options defined in the 68000 machine description:

            -m68020
            -mc68020
                 Generate output for a 68020 (rather than a 68000).  This is
                 the default if you use the unmodified sources.

            -m68000
            -mc68000
                 Generate output for a 68000 (rather than a 68020).

            -m68881
                 Generate output containing 68881 instructions for floating
                 point.  This is the default if you use the unmodified sources.



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GCC(1)                  Version 1.40(28 November 1990)                   GCC(1)


            -mfpa
                 Generate output containing Sun FPA instructions for floating
                 point.

            -msoft-float
                 Generate output containing library calls for floating point.

            -mshort
                 Consider type int to be 16 bits wide, like short int.

            -mnobitfield
                 Do not use the bit-field instructions.  -m68000 implies
                 -mnobitfield.

            -mbitfield
                 Do use the bit-field instructions.  -m68020 implies
                 -mbitfield.  This is the default if you use the unmodified
                 sources.

            -mrtd
                 Use a different function-calling convention, in which
                 functions that take a fixed number of arguments return with
                 the rtd instruction, which pops their arguments while
                 returning.  This saves one instruction in the caller since
                 there is no need to pop the arguments there.

                 This calling convention is incompatible with the one normally
                 used on Unix, so you cannot use it if you need to call
                 libraries compiled with the Unix compiler.

                 Also, you must provide function prototypes for all functions
                 that take variable numbers of arguments (including
                 printf(3S)); otherwise incorrect code will be generated for
                 calls to those functions.

                 In addition, seriously incorrect code will result if you call
                 a function with too many arguments.  (Normally, extra
                 arguments are harmlessly ignored.)

                 The rtd instruction is supported by the 68010 and 68020
                 processors, but not by the 68000.

            These -m options are defined in the Vax machine description:

            -munix
                 Do not output certain jump instructions (aobleq and so on)
                 that the Unix assembler for the Vax cannot handle across long
                 ranges.

            -mgnu
                 Do output those jump instructions, on the assumption that you
                 will assemble with the GNU assembler.


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GCC(1)                  Version 1.40(28 November 1990)                   GCC(1)


            -mg
                 Output code for g-format floating point numbers instead of d-
                 format.

            These -m switches are supported on the Sparc:

            -mfpu
                 Generate output containing floating point instructions.  This
                 is the default if you use the unmodified sources.

            -msoft-float
                 Generate output containing library calls for floating point.

            -mno-epilogue
                 Generate separate return instructions for return statements.
                 This has both advantages and disadvantages; I don't recall
                 what they are.

            These -m options are defined in the Convex machine description:

            -mc1
                 Generate output for a C1.  This is the default when the
                 compiler is configured for a C1.

            -mc2
                 Generate output for a C2.  This is the default when the
                 compiler is configured for a C2.

            -margcount
                 Generate code which puts an argument count in the word
                 preceding each argument list.  Some nonportable Convex and Vax
                 programs need this word.  (Debuggers don't; this info is in
                 the symbol table.)

            -mnoargcount
                 Omit the argument count word.  This is the default if you use
                 the unmodified sources.

      -fflag
            Specify machine-independent flags.  Most flags have both positive
            and negative forms; the negative form of -ffoo would be -fno-foo.
            In the table below, only one of the forms is listed--the one which
            is not the default.  You can figure out the other form by either
            removing no- or adding it.

      -fpcc-struct-return
            Use the same convention for returning struct and union values that
            is used by the usual C compiler on your system.  This convention is
            less efficient for small structures, and on many machines it fails
            to be reentrant; but it has the advantage of allowing
            intercallability between GCC-compiled code and PCC-compiled code.



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      -ffloat-store
            Do not store floating-point variables in registers.  This prevents
            undesirable excess precision on machines such as the 68000 where
            the floating registers (of the 68881) keep more precision than a
            double is supposed to have.

            For most programs, the excess precision does only good, but a few
            programs rely on the precise definition of IEEE floating point.
            Use -ffloat-store for such programs.

      -fno-asm
            Do not recognize asm, inline or typeof as a keyword.  These words
            may then be used as identifiers.  You can use asm, inline
            and typeof instead.

      -fno-defer-pop
            Always pop the arguments to each function call as soon as that
            function returns.  Normally the compiler (when optimizing) lets
            arguments accumulate on the stack for several function calls and
            pops them all at once.

      -fstrength-reduce
            Perform the optimizations of loop strength reduction and
            elimination of iteration variables.

      -fcombine-regs
            Allow the combine pass to combine an instruction that copies one
            register into another.  This might or might not produce better code
            when used in addition to -O.  I am interested in hearing about the
            difference this makes.

      -fforce-mem
            Force memory operands to be copied into registers before doing
            arithmetic on them.  This may produce better code by making all
            memory references potential common subexpressions.  When they are
            not common subexpressions, instruction combination should eliminate
            the separate register-load.  I am interested in hearing about the
            difference this makes.

      -fforce-addr
            Force memory address constants to be copied into registers before
            doing arithmetic on them.  This may produce better code just as
            -fforce-mem may.  I am interested in hearing about the difference
            this makes.

      -fomit-frame-pointer
            Don't keep the frame pointer in a register for functions that don't
            need one.  This avoids the instructions to save, set up and restore
            frame pointers; it also makes an extra register available in many
            functions.  It also makes debugging impossible.

            On some machines, such as the Vax, this flag has no effect, because


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            the standard calling sequence automatically handles the frame
            pointer and nothing is saved by pretending it doesn't exist.  The
            machine-description macro FRAMEPOINTERREQUIRED controls whether a
            target machine supports this flag.

      -finline-functions
            Integrate all simple functions into their callers.  The compiler
            heuristically decides which functions are simple enough to be worth
            integrating in this way.

            If all calls to a given function are integrated, and the function
            is declared static, then the function is normally not output as
            assembler code in its own right.

      -fcaller-saves
            Enable values to be allocated in registers that will be clobbered
            by function calls, by emitting extra instructions to save and
            restore the registers around such calls.  Such allocation is done
            only when it seems to result in better code than would otherwise be
            produced.

            This option is enabled by default on certain machines, usually
            those which have no call-preserved registers to use instead.

      -fkeep-inline-functions
            Even if all calls to a given function are integrated, and the
            function is declared static, nevertheless output a separate run-
            time callable version of the function.

      -fwritable-strings
            Store string constants in the writable data segment and don't
            uniquize them.  This is for compatibility with old programs which
            assume they can write into string constants.  Writing into string
            constants is a very bad idea; constants should be constant.

      -fcond-mismatch
            Allow conditional expressions with mismatched types in the second
            and third arguments.  The value of such an expression is void.

      -fno-function-cse
            Do not put function addresses in registers; make each instruction
            that calls a constant function contain the function's address
            explicitly.

            This option results in less efficient code, but some strange hacks
            that alter the assembler output may be confused by the
            optimizations performed when this option is not used.

      -fvolatile
            Consider all memory references through pointers to be volatile.




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      -fshared-data
            Requests that the data and non-const variables of this compilation
            be shared data rather than private data.  The distinction makes
            sense only on certain operating systems, where shared data is
            shared between processes running the same program, while private
            data exists in one copy per process.

      -funsigned-char
            Let the type char be the unsigned, like unsigned char.

            Each kind of machine has a default for what char should be.  It is
            either like unsigned char by default or like signed char by
            default.  (Actually, at present, the default is always signed.)

            The type char is always a distinct type from either signed char or
            unsigned char, even though its behavior is always just like one of
            those two.

            Note that this is equivalent to -fno-signed-char, which is the
            negative form of -fsigned-char.

      -fsigned-char
            Let the type char be signed, like signed char.

            Note that this is equivalent to -fno-unsigned-char, which is the
            negative form of -funsigned-char.

      -fdelayed-branch
            If supported for the target machine, attempt to reorder
            instructions to exploit instruction slots available after delayed
            branch instructions.

      -ffixed-reg
            Treat the register named reg as a fixed register; generated code
            should never refer to it (except perhaps as a stack pointer, frame
            pointer or in some other fixed role).

            reg must be the name of a register.  The register names accepted
            are machine-specific and are defined in the REGISTERNAMES macro in
            the machine description macro file.

            This flag does not have a negative form, because it specifies a
            three-way choice.

      -fcall-used-reg
            Treat the register named reg as an allocatable register that is
            clobbered by function calls.  It may be allocated for temporaries
            or variables that do not live across a call.  Functions compiled
            this way will not save and restore the register REG.

            Use of this flag for a register that has a fixed pervasive role in
            the machine's execution model, such as the stack pointer or frame


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            pointer, will produce disastrous results.

            This flag does not have a negative form, because it specifies a
            three-way choice.

      -fcall-saved-reg
            Treat the register named reg as an allocatable register saved by
            functions.  It may be allocated even for temporaries or variables
            that live across a call.  Functions compiled this way will save and
            restore the register reg if they use it.

            Use of this flag for a register that has a fixed pervasive role in
            the machine's execution model, such as the stack pointer or frame
            pointer, will produce disastrous results.

            A different sort of disaster will result from the use of this flag
            for a register in which function values may be returned.

            This flag does not have a negative form, because it specifies a
            three-way choice.

      -dletters
            Says to make debugging dumps at times specified by letters.  Here
            are the possible letters:

            r
                 Dump after RTL generation.
            j
                 Dump after first jump optimization.
            J
                 Dump after last jump optimization.
            s
                 Dump after CSE (including the jump optimization that sometimes
                 follows CSE).
            L
                 Dump after loop optimization.
            f
                 Dump after flow analysis.
            c
                 Dump after instruction combination.
            l
                 Dump after local register allocation.
            g
                 Dump after global register allocation.
            d
                 Dump after delayed branch scheduling.
            m
                 Print statistics on memory usage, at the end of the run.

      -pedantic
            Issue all the warnings demanded by strict ANSI standard C; reject
            all programs that use forbidden extensions.


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            Valid ANSI standard C programs should compile properly with or
            without this option (though a rare few will require -ansi).
            However, without this option, certain GNU extensions and
            traditional C features are supported as well.  With this option,
            they are rejected.  There is no reason to use this option; it
            exists only to satisfy pedants.

            -pedantic does not cause warning messages for use of the alternate
            keywords whose names begin and end with .

      -static
            On Suns running version 4, this prevents linking with the shared
            libraries.  (-g has the same effect.)

      These options control the C preprocessor, which is run on each C source
      file before actual compilation.  If you use the `-E' option, nothing is
      done except C preprocessing.  Some of these options make sense only
      together with `-E' because they request preprocessor output that is not
      suitable for actual compilation.

      -C    Tell the preprocessor not to discard comments.  Used with the -E
            option.

      -Idir Search directory dir for include files.

      -I-   Any directories specified with -I options before the -I- option are
            searched only for the case of #include "file"; they are not
            searched for #include <file>.

            If additional directories are specified with -I options after the
            -I-, these directories are searched for all #include directives.
            (Ordinarily all -I directories are used this way.)

            In addition, the -I- option inhibits the use of the current
            directory as the first search directory for #include "file".
            Therefore, the current directory is searched only if it is
            requested explicitly with -I..  Specifying both -I- and -I.  allows
            you to control precisely which directories are searched before the
            current one and which are searched after.

      -nostdinc
            Do not search the standard system directories for header files.
            Only the directories you have specified with -I options (and the
            current directory, if appropriate) are searched.

            Between -nostdinc and -I-, you can eliminate all directories from
            the search path except those you specify.

      -M    Tell the preprocessor to output a rule suitable for make(1)
            describing the dependencies of each source file.  For each source
            file, the preprocessor outputs one make-rule whose target is the
            object file name for that source file and whose dependencies are


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            all the files #included in it.  This rule may be a single line or
            may be continued with -newline if it is long.

            -M implies -E.

      -MM   Like -M but the output mentions only the user-header files included
            with #include "file".  System header files included with #include
            <file> are omitted.

            -MM implies -E.

      -Dmacro
            Define macro macro with the empty string as its definition.

      -Dmacro=defn
            Define macro macro as defn.

      -Umacro
            Undefine macro macro.

      -trigraphs
            Support ANSI C trigraphs.  You don't want to know about this
            brain-damage.  The -ansi option also has this effect.

FILES
      file.c             C source file
      file.s             assembly language file
      file.o             object file
      a.out              link edited output
      /tmp/cc*           temporary files
      LIBDIR/gcc-cpp     preprocessor
      LIBDIR/gcc-cc1     compiler
      LIBDIR/gcc-gnulib  library needed by GCC on some machines
      /lib/crt[01n].o    start-up routine
      /lib/libc.a        standard C library, see intro(3)
      /usr/include       standard directory for #include files
      LIBDIR/gcc-include standard gcc directory for #include files

      LIBDIR is usually /usr/local/lib.

SEE ALSO
      as(1), ld(1), adb(1), dbx(1), sdb(1).

BUGS
      Bugs should be reported to bug-gcc@prep.ai.mit.edu.  Bugs tend actually
      to be fixed if they can be isolated, so it is in your interest to report
      them in such a way that they can be easily reproduced.

COPYING
      Copyright (c) 1988 Free Software Foundation, Inc.




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      Permission is granted to make and distribute verbatim copies of this
      manual provided the copyright notice and this permission notice are
      preserved on all copies.

      Permission is granted to copy and distribute modified versions of this
      manual under the conditions for verbatim copying, provided that the
      entire resulting derived work is distributed under the terms of a
      permission notice identical to this one.

      Permission is granted to copy and distribute translations of this manual
      into another language, under the above conditions for modified versions,
      except that this permission notice may be included in translations
      approved by the Free Software Foundation instead of in the original
      English.

AUTHORS
      See the GNU CC Manual for the contributors to GNU CC.





































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