Using and Porting GNU CC

16.4: Layout of Source Language Data Types

These macros define the sizes and other characteristics of the standard basic data types used in programs being compiled. Unlike the macros in the previous section, these apply to specific features of C and related languages, rather than to fundamental aspects of storage layout.

INT_TYPE_SIZE

A C expression for the size in bits of the type int on the target machine. If you don't define this, the default is one word.

MAX_INT_TYPE_SIZE

Maximum number for the size in bits of the type int on the target machine. If this is undefined, the default is INT_TYPE_SIZE. Otherwise, it is the constant value that is the largest value that INT_TYPE_SIZE can have at run-time. This is used in cpp.

SHORT_TYPE_SIZE

A C expression for the size in bits of the type short on the target machine. If you don't define this, the default is half a word. (If this would be less than one storage unit, it is rounded up to one unit.)

LONG_TYPE_SIZE

A C expression for the size in bits of the type long on the target machine. If you don't define this, the default is one word.

MAX_LONG_TYPE_SIZE

Maximum number for the size in bits of the type long on the target machine. If this is undefined, the default is LONG_TYPE_SIZE. Otherwise, it is the constant value that is the largest value that LONG_TYPE_SIZE can have at run-time. This is used in cpp.

LONG_LONG_TYPE_SIZE

A C expression for the size in bits of the type long long on the target machine. If you don't define this, the default is two words.

CHAR_TYPE_SIZE

A C expression for the size in bits of the type char on the target machine. If you don't define this, the default is one quarter of a word. (If this would be less than one storage unit, it is rounded up to one unit.)

MAX_CHAR_TYPE_SIZE

Maximum number for the size in bits of the type char on the target machine. If this is undefined, the default is CHAR_TYPE_SIZE. Otherwise, it is the constant value that is the largest value that CHAR_TYPE_SIZE can have at run-time. This is used in cpp.

FLOAT_TYPE_SIZE

A C expression for the size in bits of the type float on the target machine. If you don't define this, the default is one word.

DOUBLE_TYPE_SIZE

A C expression for the size in bits of the type double on the target machine. If you don't define this, the default is two words.

LONG_DOUBLE_TYPE_SIZE

A C expression for the size in bits of the type long double on the target machine. If you don't define this, the default is two words.

DEFAULT_SIGNED_CHAR

An expression whose value is 1 or 0, according to whether the type char should be signed or unsigned by default. The user can always override this default with the options `-fsigned-char' and `-funsigned-char'.

DEFAULT_SHORT_ENUMS

A C expression to determine whether to give an enum type only as many bytes as it takes to represent the range of possible values of that type. A nonzero value means to do that; a zero value means all enum types should be allocated like int.

If you don't define the macro, the default is 0.

SIZE_TYPE

A C expression for a string describing the name of the data type to use for size values. The typedef name size_t is defined using the contents of the string.

The string can contain more than one keyword. If so, separate them with spaces, and write first any length keyword, then unsigned if appropriate, and finally int. The string must exactly match one of the data type names defined in the function init_decl_processing in the file `c-decl.c'. You may not omit int or change the order---that would cause the compiler to crash on startup.

If you don't define this macro, the default is "long unsigned int".

PTRDIFF_TYPE

A C expression for a string describing the name of the data type to use for the result of subtracting two pointers. The typedef name ptrdiff_t is defined using the contents of the string. See SIZE_TYPE above for more information.

If you don't define this macro, the default is "long int".

WCHAR_TYPE

A C expression for a string describing the name of the data type to use for wide characters. The typedef name wchar_t is defined using the contents of the string. See SIZE_TYPE above for more information.

If you don't define this macro, the default is "int".

WCHAR_TYPE_SIZE

A C expression for the size in bits of the data type for wide characters. This is used in cpp, which cannot make use of WCHAR_TYPE.

MAX_WCHAR_TYPE_SIZE

Maximum number for the size in bits of the data type for wide characters. If this is undefined, the default is WCHAR_TYPE_SIZE. Otherwise, it is the constant value that is the largest value that WCHAR_TYPE_SIZE can have at run-time. This is used in cpp.

OBJC_INT_SELECTORS

Define this macro if the type of Objective C selectors should be int.

If this macro is not defined, then selectors should have the type struct objc_selector *.

OBJC_SELECTORS_WITHOUT_LABELS

Define this macro if the compiler can group all the selectors together into a vector and use just one label at the beginning of the vector. Otherwise, the compiler must give each selector its own assembler label.

On certain machines, it is important to have a separate label for each selector because this enables the linker to eliminate duplicate selectors.

TARGET_BELL

A C constant expression for the integer value for escape sequence `\a'.

TARGET_BS

TARGET_TAB

TARGET_NEWLINE

C constant expressions for the integer values for escape sequences `\b', `\t' and `\n'.

TARGET_VT

TARGET_FF

TARGET_CR

C constant expressions for the integer values for escape sequences `\v', `\f' and `\r'.