GCC common switches
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The following is an edited list of the command line switches for RISC OS GCC 3.4.6 release 3. GCC has many options, and only those most of interest to RISC OS users are listed here. The full list may be obtained with *gcc --help -v
--help Display this information
-dumpspecs Display all of the built in spec strings
-dumpversion Display the version of the compiler
-dumpmachine Display the compiler's target processor
-Wa,<options> Pass comma-separated <options> on to the assembler
-Wp,<options> Pass comma-separated <options> on to the preprocessor
-Wl,<options> Pass comma-separated <options> on to the linker
-Xassembler <arg> Pass <arg> on to the assembler
-Xpreprocessor <arg> Pass <arg> on to the preprocessor
-Xlinker <arg> Pass <arg> on to the linker
-v Display the programs invoked by the compiler
-### Like -v but options quoted and commands not executed
-E Preprocess only; do not compile, assemble or link
-S Compile only; do not assemble or link
-c Compile and assemble, but do not link
-o <file> Place the output into <file>
-x <language> Specify the language of the following input files
Permissible languages include: c c++ assembler none
'none' means revert to the default behavior of
guessing the language based on the file's extension
Options starting with -g, -f, -m, -O, -W, or --param are automatically
passed on to the various sub-processes invoked by gcc. In order to pass
other options on to these processes the -W<letter> options must be used.
GCC compiler options
--help Display this information
--version This switch lacks documentation
-O<number> Set optimization level to <number>
-Os Optimize for space rather than speed
-Werror Treat all warnings as errors
-Wextra Print extra (possibly unwanted) warnings
-fPIC This switch lacks documentation
-funroll-all-loops Perform loop unrolling for all loops
-funroll-loops Perform loop unrolling when iteration count is
known
-g Generate debug information in default format
-o <file> Place output into <file>
-p Enable function profiling
-pedantic Issue warnings needed for strict compliance to
the standard
-pedantic-errors Like -pedantic but issue them as errors
-quiet Do not display functions compiled or elapsed time
-version Display the compiler's version
-w Suppress warnings
C/C++ options
-U<macro> Undefine <macro>
-Wall This switch lacks documentation
-Wdeclaration-after-statement Warn when a declaration is found after a
statement
-Wdiv-by-zero Warn about compile-time integer division by zero
-Wformat Warn about printf/scanf/strftime/strfmon format
string anomalies
-Wformat-extra-args Warn if passing too many arguments to a function
for its format string
-Wlong-long Do not warn about using "long long" when -pedantic
-Wmissing-braces Warn about possibly missing braces around
initializers
-Wmissing-declarations Warn about global functions without previous
declarations
-Wmissing-format-attribute Warn about functions which might be candidates
for format attributes
-Wmissing-prototypes Warn about global functions without prototypes
-ansi A synonym for -std=c89 (for C) or -std=c++98 (for
C++).
-icrossdirafter <dir> Add <dir> to the end of the system include path
-idirafter <dir> Add <dir> to the end of the system include path
-imacros <file> Accept definition of macros in <file>
-include <file> Include the contents of <file> before other files
-iprefix <path> Specify <path> as a prefix for next two options
-isysroot <dir> Set <dir> to be the system root directory
-isystem <dir> Add <dir> to the start of the system include path
-iwithprefix <dir> Add <dir> to the end of the system include path
-iwithprefixbefore <dir> Add <dir> to the end of the main include path
-nostdinc Do not search standard system include directories
(those specified with -isystem will still be used)
-remap Remap file names when including files
-std=c89 Conform to the ISO 1990 C standard
-std=c99 Conform to the ISO 1999 C standard
-std=c9x Deprecated in favor of -std=c99
-std=gnu89 Conform to the ISO 1990 C standard with GNU
extensions
-std=gnu99 Conform to the ISO 1999 C standard with GNU
extensions
-std=gnu9x Deprecated in favor of -std=gnu99
-std=iso9899:1990 Conform to the ISO 1990 C standard
-std=iso9899:199409 Conform to the ISO 1990 C standard as amended in
1994
-std=iso9899:1999 Conform to the ISO 1999 C standard
-std=iso9899:199x Deprecated in favor of -std=iso9899:1999
-traditional-cpp Enable traditional preprocessing
-undef Do not predefine system-specific and GCC-specific
macros
-v Enable verbose output
C++ options
-fxref Emit cross referencing information
-nostdinc++ Do not search standard system include directories
for C++
-std=c++98 Conform to the ISO 1998 C++ standard
-std=gnu++98 Conform to the ISO 1998 C++ standard with GNU
extensions
RISC OS/ARM specific options
-mmodule Generate data references suitable for RISC OS modules -munixlib Compile with the headers from UnixLib (default) -mlibscl Compile with the SharedCLibrary headers -mamu Format source dependencies for Acorn's Make Utility -mthrowback Send errors to a DDEUtils compatible text editor -mhard-float Use hardware floating point instructions -msoft-float Use library calls to perform FP operations -mapcs-reentrant Generate re-entrant, PIC code -mapcs-float Pass FP arguments in FP registers -mapcs-32 Use the 32-bit version of the APCS -mpoke-function-name Store function names in object code -mapcs-frame Generate APCS conformant stack frames -mpic-register= Specify the register to be used for PIC addressing -mstructure-size-boundary= Specify the minimum bit alignment of structures -mfp= Specify the version of the floating point emulator -march= Specify the name of the target architecture (eg armv4l) -mcpu= Specify the name of the target CPU (eg arm610)
