cobalt/site/docs/reference/starboard/modules/13/configuration.md - cobalt.git - Git at Google

 Project: /youtube/cobalt/_project.yaml
 Book: /youtube/cobalt/_book.yaml

 # Starboard Module Reference: `configuration.h`

 Provides a description of the current platform in lurid detail so that common
 code never needs to actually know what the current operating system and
 architecture are.

 It is both very pragmatic and canonical in that if any application code finds
 itself needing to make a platform decision, it should always define a Starboard
 Configuration feature instead. This implies the continued existence of very
 narrowly-defined configuration features, but it retains porting control in
 Starboard.

 ## Macros

 ### SB_ALIGNAS(byte_alignment)

 Specifies the alignment for a class, struct, union, enum, class/struct field, or
 stack variable.

 ### SB_ALIGNOF(type)

 Returns the alignment required for any instance of the type indicated by `type`.

 ### SB_ARRAY_SIZE(array)

 A constant expression that evaluates to the size_t size of a statically-sized
 array.

 ### SB_ARRAY_SIZE_INT(array)

 A constant expression that evaluates to the int size of a statically-sized
 array.

 ### SB_CAN(SB_FEATURE)

 Determines a compile-time capability of the system.

 ### SB_COMPILE_ASSERT(expr, msg)

 Will cause a compiler error with `msg` if `expr` is false. `msg` must be a valid
 identifier, and must be a unique type in the scope of the declaration.

 ### SB_DEPRECATED(FUNC)

 SB_DEPRECATED(int Foo(int bar)); Annotates the function as deprecated, which
 will trigger a compiler warning when referenced.

 ### SB_DEPRECATED_EXTERNAL(FUNC)

 SB_DEPRECATED_EXTERNAL(...) annotates the function as deprecated for external
 clients, but not deprecated for starboard.

 ### SB_EXPERIMENTAL_API_VERSION

 The API version that is currently open for changes, and therefore is not stable
 or frozen. Production-oriented ports should avoid declaring that they implement
 the experimental Starboard API version.

 ### SB_FUNCTION

 Whether we use **PRETTY_FUNCTION** PRETTY_FUNCTION or **FUNCTION** FUNCTION for
 logging.

 ### SB_HAS(SB_FEATURE)

 Determines at compile-time whether this platform has a standard feature or
 header available.

 ### SB_HAS_64_BIT_ATOMICS

 Whether the current platform has 64-bit atomic operations.

 ### SB_HAS_GLES2

 Specifies whether this platform has a performant OpenGL ES 2 implementation,
 which allows client applications to use GL rendering paths. Derived from the gyp
 variable `gl_type` gl_type which indicates what kind of GL implementation is
 available.

 ### SB_HAS_QUIRK(SB_FEATURE)

 Determines at compile-time whether this platform has a quirk.

 ### SB_INT64_C(x)

 Declare numeric literals of signed 64-bit type.

 ### SB_IS(SB_FEATURE)

 Determines at compile-time an inherent aspect of this platform.

 ### SB_LIKELY(x)

 Macro for hinting that an expression is likely to be true.

 ### SB_MAXIMUM_API_VERSION

 The maximum API version allowed by this version of the Starboard headers,
 inclusive.

 ### SB_MINIMUM_API_VERSION

 The minimum API version allowed by this version of the Starboard headers,
 inclusive.

 ### SB_NORETURN

 Macro to annotate a function as noreturn, which signals to the compiler that the
 function cannot return.

 ### SB_OVERRIDE

 Declares a function as overriding a virtual function on compilers that support
 it.

 ### SB_PREFERRED_RGBA_BYTE_ORDER_RGBA

 An enumeration of values for the kSbPreferredByteOrder configuration variable.
 Setting this up properly means avoiding slow color swizzles when passing pixel
 data from one library to another. Note that these definitions are in byte-order
 and so are endianness-independent.

 ### SB_PRINTF_FORMAT(format_param, dots_param)

 Tells the compiler a function is using a printf-style format string.
 `format_param` is the one-based index of the format string parameter;
 `dots_param` is the one-based index of the "..." parameter. For v*printf
 functions (which take a va_list), pass 0 for dots_param. (This is undocumented
 but matches what the system C headers do.) (Partially taken from
 base/compiler_specific.h)

 ### SB_RESTRICT

 Include the platform-specific configuration. This macro is set by GN in
 starboard/build/config/BUILD.gn and passed in on the command line for all
 targets and all configurations.Makes a pointer-typed parameter restricted so
 that the compiler can make certain optimizations because it knows the pointers
 are unique.

 ### SB_SIZE_OF(DATATYPE)

 Determines at compile-time the size of a data type, or 0 if the data type that
 was specified was invalid.

 ### SB_STRINGIFY(x)

 Standard CPP trick to stringify an evaluated macro definition.

 ### SB_UINT64_C(x)

 Declare numeric literals of unsigned 64-bit type.

 ### SB_UNLIKELY(x)

 Macro for hinting that an expression is likely to be false.

 ### SB_UNREFERENCED_PARAMETER(x)

 Trivially references a parameter that is otherwise unreferenced, preventing a
 compiler warning on some platforms.

 ### SB_WARN_UNUSED_RESULT

 Causes the annotated (at the end) function to generate a warning if the result
 is not accessed.
	Project: /youtube/cobalt/_project.yaml
	Book: /youtube/cobalt/_book.yaml

	# Starboard Module Reference: `configuration.h`

	Provides a description of the current platform in lurid detail so that common
	code never needs to actually know what the current operating system and
	architecture are.

	It is both very pragmatic and canonical in that if any application code finds
	itself needing to make a platform decision, it should always define a Starboard
	Configuration feature instead. This implies the continued existence of very
	narrowly-defined configuration features, but it retains porting control in
	Starboard.

	## Macros

	### SB_ALIGNAS(byte_alignment)

	Specifies the alignment for a class, struct, union, enum, class/struct field, or
	stack variable.

	### SB_ALIGNOF(type)

	Returns the alignment required for any instance of the type indicated by `type`.

	### SB_ARRAY_SIZE(array)

	A constant expression that evaluates to the size_t size of a statically-sized
	array.

	### SB_ARRAY_SIZE_INT(array)

	A constant expression that evaluates to the int size of a statically-sized
	array.

	### SB_CAN(SB_FEATURE)

	Determines a compile-time capability of the system.

	### SB_COMPILE_ASSERT(expr, msg)

	Will cause a compiler error with `msg` if `expr` is false. `msg` must be a valid
	identifier, and must be a unique type in the scope of the declaration.

	### SB_DEPRECATED(FUNC)

	SB_DEPRECATED(int Foo(int bar)); Annotates the function as deprecated, which
	will trigger a compiler warning when referenced.

	### SB_DEPRECATED_EXTERNAL(FUNC)

	SB_DEPRECATED_EXTERNAL(...) annotates the function as deprecated for external
	clients, but not deprecated for starboard.

	### SB_EXPERIMENTAL_API_VERSION

	The API version that is currently open for changes, and therefore is not stable
	or frozen. Production-oriented ports should avoid declaring that they implement
	the experimental Starboard API version.

	### SB_FUNCTION

	Whether we use PRETTY_FUNCTION PRETTY_FUNCTION or FUNCTION FUNCTION for
	logging.

	### SB_HAS(SB_FEATURE)

	Determines at compile-time whether this platform has a standard feature or
	header available.

	### SB_HAS_64_BIT_ATOMICS

	Whether the current platform has 64-bit atomic operations.

	### SB_HAS_GLES2

	Specifies whether this platform has a performant OpenGL ES 2 implementation,
	which allows client applications to use GL rendering paths. Derived from the gyp
	variable `gl_type` gl_type which indicates what kind of GL implementation is
	available.

	### SB_HAS_QUIRK(SB_FEATURE)

	Determines at compile-time whether this platform has a quirk.

	### SB_INT64_C(x)

	Declare numeric literals of signed 64-bit type.

	### SB_IS(SB_FEATURE)

	Determines at compile-time an inherent aspect of this platform.

	### SB_LIKELY(x)

	Macro for hinting that an expression is likely to be true.

	### SB_MAXIMUM_API_VERSION

	The maximum API version allowed by this version of the Starboard headers,
	inclusive.

	### SB_MINIMUM_API_VERSION

	The minimum API version allowed by this version of the Starboard headers,
	inclusive.

	### SB_NORETURN

	Macro to annotate a function as noreturn, which signals to the compiler that the
	function cannot return.

	### SB_OVERRIDE

	Declares a function as overriding a virtual function on compilers that support
	it.

	### SB_PREFERRED_RGBA_BYTE_ORDER_RGBA

	An enumeration of values for the kSbPreferredByteOrder configuration variable.
	Setting this up properly means avoiding slow color swizzles when passing pixel
	data from one library to another. Note that these definitions are in byte-order
	and so are endianness-independent.

	### SB_PRINTF_FORMAT(format_param, dots_param)

	Tells the compiler a function is using a printf-style format string.
	`format_param` is the one-based index of the format string parameter;
	`dots_param` is the one-based index of the "..." parameter. For v*printf
	functions (which take a va_list), pass 0 for dots_param. (This is undocumented
	but matches what the system C headers do.) (Partially taken from
	base/compiler_specific.h)

	### SB_RESTRICT

	Include the platform-specific configuration. This macro is set by GN in
	starboard/build/config/BUILD.gn and passed in on the command line for all
	targets and all configurations.Makes a pointer-typed parameter restricted so
	that the compiler can make certain optimizations because it knows the pointers
	are unique.

	### SB_SIZE_OF(DATATYPE)

	Determines at compile-time the size of a data type, or 0 if the data type that
	was specified was invalid.

	### SB_STRINGIFY(x)

	Standard CPP trick to stringify an evaluated macro definition.

	### SB_UINT64_C(x)

	Declare numeric literals of unsigned 64-bit type.

	### SB_UNLIKELY(x)

	Macro for hinting that an expression is likely to be false.

	### SB_UNREFERENCED_PARAMETER(x)

	Trivially references a parameter that is otherwise unreferenced, preventing a
	compiler warning on some platforms.

	### SB_WARN_UNUSED_RESULT

	Causes the annotated (at the end) function to generate a warning if the result
	is not accessed.