-@c Copyright (c) 1999, 2000, 2001, 2002
+@c Copyright (c) 1999, 2000, 2001, 2002, 2003, 2004, 2005
@c Free Software Foundation, Inc.
@c This is part of the CPP and GCC manuals.
@c For copying conditions, see the file gcc.texi.
Predefine @var{name} as a macro, with definition @code{1}.
@item -D @var{name}=@var{definition}
-Predefine @var{name} as a macro, with definition @var{definition}.
-There are no restrictions on the contents of @var{definition}, but if
-you are invoking the preprocessor from a shell or shell-like program you
-may need to use the shell's quoting syntax to protect characters such as
-spaces that have a meaning in the shell syntax.
+The contents of @var{definition} are tokenized and processed as if
+they appeared during translation phase three in a @samp{#define}
+directive. In particular, the definition will be truncated by
+embedded newline characters.
+
+If you are invoking the preprocessor from a shell or shell-like
+program you may need to use the shell's quoting syntax to protect
+characters such as spaces that have a meaning in the shell syntax.
If you wish to define a function-like macro on the command line, write
its argument list with surrounding parentheses before the equals sign
@item -undef
@opindex undef
-Do not predefine any system-specific macros. The common predefined
-macros remain defined.
+Do not predefine any system-specific or GCC-specific macros. The
+standard predefined macros remain defined.
+@ifset cppmanual
+@xref{Standard Predefined Macros}.
+@end ifset
@item -I @var{dir}
@opindex I
@xref{Search Path}.
@end ifset
Directories named by @option{-I} are searched before the standard
-system include directories.
-
-It is dangerous to specify a standard system include directory in an
-@option{-I} option. This defeats the special treatment of system
-headers
+system include directories. If the directory @var{dir} is a standard
+system include directory, the option is ignored to ensure that the
+default search order for system directories and the special treatment
+of system headers are not defeated
@ifset cppmanual
(@pxref{System Headers})
@end ifset
-. It can also defeat the repairs to buggy system headers which GCC
-makes when it is installed.
+.
@item -o @var{file}
@opindex o
@item -Wall
@opindex Wall
-Turns on all optional warnings which are desirable for normal code. At
-present this is @option{-Wcomment} and @option{-Wtrigraphs}. Note that
-many of the preprocessor's warnings are on by default and have no
-options to control them.
+Turns on all optional warnings which are desirable for normal code.
+At present this is @option{-Wcomment}, @option{-Wtrigraphs},
+@option{-Wmultichar} and a warning about integer promotion causing a
+change of sign in @code{#if} expressions. Note that many of the
+preprocessor's warnings are on by default and have no options to
+control them.
@item -Wcomment
@itemx -Wcomments
@item -Wtrigraphs
@opindex Wtrigraphs
-Warn if any trigraphs are encountered. This option used to take effect
-only if @option{-trigraphs} was also specified, but now works
-independently. Warnings are not given for trigraphs within comments, as
-they do not affect the meaning of the program.
+@anchor{Wtrigraphs}
+Most trigraphs in comments cannot affect the meaning of the program.
+However, a trigraph that would form an escaped newline (@samp{??/} at
+the end of a line) can, by changing where the comment begins or ends.
+Therefore, only trigraphs that would form escaped newlines produce
+warnings inside a comment.
+
+This option is implied by @option{-Wall}. If @option{-Wall} is not
+given, this option is still enabled unless trigraphs are enabled. To
+get trigraph conversion without warnings, but get the other
+@option{-Wall} warnings, use @samp{-trigraphs -Wall -Wno-trigraphs}.
@item -Wtraditional
@opindex Wtraditional
Built-in macros, macros defined on the command line, and macros
defined in include files are not warned about.
-@strong{Note:} If a macro is actually used, but only used in skipped
+@emph{Note:} If a macro is actually used, but only used in skipped
conditional blocks, then CPP will report it as unused. To avoid the
warning in such a case, you might improve the scope of the macro's
definition by, for example, moving it into the first skipped block.
header will appear in @option{-MM} dependency output. This is a
slight change in semantics from GCC versions 3.0 and earlier.
+@anchor{dashMF}
@item -MF @var{file}
@opindex MF
-@anchor{-MF}
When used with @option{-M} or @option{-MM}, specifies a
file to write the dependencies to. If no @option{-MF} switch is given
the preprocessor sends the rules to the same place it would have sent
This is typical output:
-@example
+@smallexample
test.o: test.c test.h
test.h:
-@end example
+@end smallexample
@item -MT @var{target}
@opindex MT
For example, @option{@w{-MT '$(objpfx)foo.o'}} might give
-@example
+@smallexample
$(objpfx)foo.o: foo.c
-@end example
+@end smallexample
@item -MQ @var{target}
@opindex MQ
Same as @option{-MT}, but it quotes any characters which are special to
Make. @option{@w{-MQ '$(objpfx)foo.o'}} gives
-@example
+@smallexample
$$(objpfx)foo.o: foo.c
-@end example
+@end smallexample
The default target is automatically quoted, as if it were given with
@option{-MQ}.
If @option{-MD} is used in conjunction with @option{-E}, any
@option{-o} switch is understood to specify the dependency output file
-(but @pxref{-MF}), but if used without @option{-E}, each @option{-o}
+(but @pxref{dashMF,,-MF}), but if used without @option{-E}, each @option{-o}
is understood to specify a target object file.
Since @option{-E} is not implied, @option{-MD} can be used to generate
@item -MMD
@opindex MMD
Like @option{-MD} except mention only user header files, not system
--header files.
+header files.
+
+@ifclear cppmanual
+@item -fpch-deps
+@opindex fpch-deps
+When using precompiled headers (@pxref{Precompiled Headers}), this flag
+will cause the dependency-output flags to also list the files from the
+precompiled header's dependencies. If not specified only the
+precompiled header would be listed and not the files that were used to
+create it because those files are not consulted when a precompiled
+header is used.
+
+@item -fpch-preprocess
+@opindex fpch-preprocess
+This option allows use of a precompiled header (@pxref{Precompiled
+Headers}) together with @option{-E}. It inserts a special @code{#pragma},
+@code{#pragma GCC pch_preprocess "<filename>"} in the output to mark
+the place where the precompiled header was found, and its filename. When
+@option{-fpreprocessed} is in use, GCC recognizes this @code{#pragma} and
+loads the PCH@.
+
+This option is off by default, because the resulting preprocessed output
+is only really suitable as input to GCC@. It is switched on by
+@option{-save-temps}.
+
+You should not write this @code{#pragma} in your own code, but it is
+safe to edit the filename if the PCH file is available in a different
+location. The filename may be absolute or it may be relative to GCC's
+current directory.
+@end ifclear
@item -x c
@itemx -x c++
@itemx -x objective-c
recognize the extension, it will treat the file as C; this is the most
generic mode.
-@strong{Note:} Previous versions of cpp accepted a @option{-lang} option
+@emph{Note:} Previous versions of cpp accepted a @option{-lang} option
which selected both the language and the standards conformance level.
This option has been removed, because it conflicts with the @option{-l}
option.
@ifset cppmanual
@xref{Search Path}.
@end ifset
+This option has been deprecated.
@item -nostdinc
@opindex nostdinc
path. @option{-iwithprefixbefore} puts it in the same place @option{-I}
would; @option{-iwithprefix} puts it where @option{-idirafter} would.
-Use of these options is discouraged.
-
@item -isystem @var{dir}
@opindex isystem
Search @var{dir} for header files, after all directories specified by
@xref{System Headers}.
@end ifset
+@item -iquote @var{dir}
+@opindex iquote
+Search @var{dir} only for header files requested with
+@code{@w{#include "@var{file}"}}; they are not searched for
+@code{@w{#include <@var{file}>}}, before all directories specified by
+@option{-I} and before the standard system directories.
+@ifset cppmanual
+@xref{Search Path}.
+@end ifset
+
+@item -fdollars-in-identifiers
+@opindex fdollars-in-identifiers
+@anchor{fdollars-in-identifiers}
+Accept @samp{$} in identifiers.
+@ifset cppmanual
+ @xref{Identifier characters}.
+@end ifset
+
@item -fpreprocessed
@opindex fpreprocessed
Indicate to the preprocessor that the input file has already been
line. If the value is less than 1 or greater than 100, the option is
ignored. The default is 8.
+@item -fexec-charset=@var{charset}
+@opindex fexec-charset
+@cindex character set, execution
+Set the execution character set, used for string and character
+constants. The default is UTF-8. @var{charset} can be any encoding
+supported by the system's @code{iconv} library routine.
+
+@item -fwide-exec-charset=@var{charset}
+@opindex fwide-exec-charset
+@cindex character set, wide execution
+Set the wide execution character set, used for wide string and
+character constants. The default is UTF-32 or UTF-16, whichever
+corresponds to the width of @code{wchar_t}. As with
+@option{-fexec-charset}, @var{charset} can be any encoding supported
+by the system's @code{iconv} library routine; however, you will have
+problems with encodings that do not fit exactly in @code{wchar_t}.
+
+@item -finput-charset=@var{charset}
+@opindex finput-charset
+@cindex character set, input
+Set the input character set, used for translation from the character
+set of the input file to the source character set used by GCC@. If the
+locale does not specify, or GCC cannot get this information from the
+locale, the default is UTF-8. This can be overridden by either the locale
+or this command line option. Currently the command line option takes
+precedence if there's a conflict. @var{charset} can be any encoding
+supported by the system's @code{iconv} library routine.
+
+@item -fworking-directory
+@opindex fworking-directory
+@opindex fno-working-directory
+Enable generation of linemarkers in the preprocessor output that will
+let the compiler know the current working directory at the time of
+preprocessing. When this option is enabled, the preprocessor will
+emit, after the initial linemarker, a second linemarker with the
+current working directory followed by two slashes. GCC will use this
+directory, when it's present in the preprocessed input, as the
+directory emitted as the current working directory in some debugging
+information formats. This option is implicitly enabled if debugging
+information is enabled, but this can be inhibited with the negated
+form @option{-fno-working-directory}. If the @option{-P} flag is
+present in the command line, this option has no effect, since no
+@code{#line} directives are emitted whatsoever.
+
@item -fno-show-column
@opindex fno-show-column
Do not print column numbers in diagnostics. This may be necessary if
Cancel an assertion with the predicate @var{predicate} and answer
@var{answer}.
-@item -A-
-@opindex A-
-Cancel all predefined assertions and all assertions preceding it on
-the command line. Also, undefine all predefined macros and all
-macros preceding it on the command line. (This is a historical wart and
-may change in the future.)
-
@item -dCHARS
@var{CHARS} is a sequence of one or more of the following characters,
and must not be preceded by a space. Other characters are interpreted
finding out what is predefined in your version of the preprocessor.
Assuming you have no file @file{foo.h}, the command
-@example
+@smallexample
touch foo.h; cpp -dM foo.h
-@end example
+@end smallexample
@noindent
will show all the predefined macros.
In addition to the side-effects of the @option{-C} option, the
@option{-CC} option causes all C++-style comments inside a macro
to be converted to C-style comments. This is to prevent later use
-of that macro from inadvertently commenting out the remainer of
+of that macro from inadvertently commenting out the remainder of
the source line.
The @option{-CC} option is generally used to support lint comments.
-@item -gcc
-@opindex gcc
-Define the macros @sc{__gnuc__}, @sc{__gnuc_minor__} and
-@sc{__gnuc_patchlevel__}. These are defined automatically when you use
-@command{gcc -E}; you can turn them off in that case with
-@option{-no-gcc}.
-
@item -traditional-cpp
@opindex traditional-cpp
Try to imitate the behavior of old-fashioned C preprocessors, as
The nine trigraphs and their replacements are
-@example
+@smallexample
Trigraph: ??( ??) ??< ??> ??= ??/ ??' ??! ??-
Replacement: [ ] @{ @} # \ ^ | ~
-@end example
+@end smallexample
@end ifclear
@item -remap
@opindex H
Print the name of each header file used, in addition to other normal
activities. Each name is indented to show how deep in the
-@samp{#include} stack it is.
+@samp{#include} stack it is. Precompiled header files are also
+printed, even if they are found to be invalid; an invalid precompiled
+header file is printed with @samp{...x} and a valid one with @samp{...!} .
@item -version
@itemx --version
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