NAME

SYNOPSIS

DESCRIPTION

OPTIONS

-c

Compile the input files to object files. The default output filename is the input filename with the extension replaced by .o.

-S

Compile the input files to assembler. The default output filename is the input filename with the extension replaced by .s.

-E

Preprocess the input file only. By default the result is output to stdout.

--print-ast

Output the abstract syntax tree of the parsed input file as C again.

--print-implicit-cast

When using --print-ast, show casts, which are inserted by the semantic checks.

--print-parenthesis

When using --print-ast, show all expressions fully parenthesized.

-ansi

Same as -std=c90 (for C) or -std=c++98 (for C++).

-std=standard

Select the language standard. Supported values are:

c89

 

c90

 

iso9899:1990

ISO C90

gnu89

ISO C90 with GCC extensions

c99

 

iso9899:1999

ISO C99

gnu99

ISO C99 with GCC extensions

c11

 

iso9899:2011

ISO C11

gnu11

ISO C11 with GCC extensions

c++98

ISO C++ 1998. Not supported yet.

gnu++98

ISO C++ 1998 with GCC extensions. Not supported yet.

--[no-]gcc

Disable/enable GCC extensions. This switch supersedes -std.

--[no-]ms

Disable/enable MSC extensions.

-g

When compiling C files, add debug information in stabs format.

-Olevel

Select the optimization level. Sensible values are between 0 and 4, inclusive.

-Wwarning

Enable the specified warning.

-Wno-warning

Disable the specified warning.

-Werror=warning

Enable the specified warning and turn it into an error.

-Wno-error=warning

Force the specified warning to only be a warning, even in the presence of -Werror. This neither enables nor disables the warning itself.

-Waddress

Warn about suspicious use of addresses, like using the address of a function or variable as boolean condition or comparing with the address of a string literal.

-Waggregate-return

Warn about defining or calling a function, which returns a struct or union by value.

-Wall

Activate most warnings. In particular these are -Waddress, -Wattribute, -Wchar-subscripts, -Wcomment, -Wempty-statement, -Wformat, -Wimplicit-function-declaration, -Wimplicit-int, -Winit-self, -Wmain, -Wnonnull, -Wparentheses, -Wpointer-arith, -Wredundant-decls, -Wreturn-type, -Wshadow-local, -Wsign-compare, -Wstrict-prototypes, -Wswitch-enum, -Wunknown-pragmas, -Wunreachable-code, -Wunused-function, -Wunused-label, -Wunused-parameter, -Wunused-value, -Wunused-variable.

-Wcast-qual

Warn whenever a pointer cast removes qualifiers from the pointed-to type, e.g. casting a const char* to char*.

-Wchar-subscripts

Warn about using an expression of type char as array subscript, e.g. char c; arr[c].

-Wdeclaration-after-statement

Warn about mixing declarations and statements, which is not allowed prior to C99.

-Wdiv-by-zero

Warn about compile-time integer division by zero.

-Wempty-statement

Warn about empty statements, i.e. statements which only consist of a single ‘;’. Use {} as replacement to avoid this warning.

-Werror

Treat warnings as errors, i.e. do not continue after parsing when a warning is encountered.

-Wextra

(Alias -W) Activate some more warnings. In particular these are -Wempty-statement, -Wshadow, -Wunused-parameter, -Wunused-value.

-Wfatal-errors

Immediately abort compilation when encountering an error.

-Wformat

Check format strings of char and wchar_t functions.

-Wimplicit

Activate -Wimplicit-function-declaration, -Wimplicit-int.

-Wimplicit-function-declaration

Warn about calling a function without a prior declaration.

-Wimplicit-int

Warn about declarations whose declaration specifiers do not include a type specifier.

-Winit-self

Warn about uninitialized variables which are initialized with themselves.

-Wlong-long

Warn if the type ‘long long’ is used.

-Wmain

Warn if the type of ‘main’ is suspicious, i.e. if it is not a non-static function declared as either int main(void), int main(int, char**) or, as an extension, int main(int, char**, char**).

-Wmissing-declarations

Warn if a non-static function or a global variable without a storage class is defined without a prior declaration. This is typically a sign of a missing #include or that the object should be static.

-Wmissing-noreturn

Warn about functions, which are candidates for the attribute ‘noreturn’.

-Wmissing-prototypes

Warn if a global function is defined without a previous prototype declaration.

-Wmultichar

Warn if a multicharacter constant (‘FOOF’) is used.

-Wnested-externs

Warn if an ‘extern’ declaration is encountered within a function.

-Wparentheses

Warn if parentheses are omitted in certain contexts. Warn if an assignment is used as condition, e.g. if (x = 23). Warn if && without parentheses is used within ||, e.g. if (x || y && z). Warn if it there may be confusion which ‘if’-statement an ‘else’-branch belongs to, e.g. if (x) if (y) {} else {}. Warn if cascaded comparisons appear which do not have their mathematical meaning, e.g. if (23 <= x < 42). Warn if + or - is used as operand of << or >>, e.g. x + y << z.

-Wredundant-decls

Warn about redundant declarations, i.e. multiple declarations of the same object or static forward declarations which have no use before their definition.

-Wshadow

Warn when a new declaration shadows another declaration with the same name in an outer scope.

-Wshadow-local

Like -Wshadow, but only warn if the shadowed declaration is not global, e.g. a local variable shadows a parameter or another local variable.

-Wunreachable-code

Warn when the compiler determines that a statement (or in some cases a part thereof) will never be executed.

-Wunused

Activate -Wunused-function, -Wunused-label, -Wunused-parameter, -Wunused-value, -Wunused-variable.

-Wunused-parameter

Warn when a parameter is never used or only ever read to calculate its own new value, e.g. x = x + 1.

-Wunused-variable

Warn when a variable is never used or only ever read to calculate its own new value, e.g. x = x + 1.

-w

Suppress all warnings.

-I dir

Add the directory dir to the paths to be searched for include files.

-L dir

Add the directory dir to the paths to be searched for libraries.

-Dmacro

Define the preprocessor macro macro which will expand to 1.

-Dmacro=defn

Define the preprocessor macro macro and set its expanded value to defn.

-Umacro

Undefine the preprocessor macro macro.

-f option

Set a frontend or optimizer option. Use -fhelp to get a list of supported optimizer options.

-f[no-]diagnostics-show-option

Show the switch, which controls a warning, after each warning. Default is on.

-finput-charset=encoding

Select the encoding of the input. Supported values are ISO_8859-1:1987 (aliases CP819, IBM819, ISO-8859-1, ISO8859-1, ISO_8859-1, csISOLatin1, iso-ir-100, l1 and latin1), ISO-8859-15 (aliases ISO8859-15, ISO_8859-15 and Latin-9), windows-1252 (alias cp1252) and UTF-8 (default). Case is ignored.

-f[no-]show-column

Show the column number in diagnostic messages.

-fsigned-char

Define ‘char’ to have the same range, representation and behaviour as ‘signed char’.

-funsigned-char

Define ‘char’ to have the same range, representation and behaviour as ‘unsigned char’.

-b option

Set a backend option. Use -bhelp to get a list of supported options.

-l library

Link with the specified library.

-o outfile

Specify the output filename. This is only valid when using a single input filename. - as filename uses stdout for output.

-x language

Overwrite the language auto-detection for the following filenames by the specified language. Supported values are:

assembler

Assembler file

assembler-with-cpp

Assembler file, which needs to be preprocessed

c

 

c-header

C file

c++

 

c++-header

C++ file

none

Revert to auto-detection

-Wl,option

Pass option to the linker.

-Wp,option

Pass option to the preprocessor.

SEE ALSO

BUGS

cparser needs to support more switches for better GCC compatibility.

This manual page is incomplete.

AUTHORS