Objects

Collaboration diagram for Objects:

Namespaces
	FSTR

Macros
#define	DECLARE_FSTR_OBJECT(name, ObjectType)   extern const ObjectType& name;
	Declare a global Object reference. More...
#define	DEFINE_FSTR_REF(name, ObjectType, object)   const ObjectType& name PROGMEM = object.template as<ObjectType>();
	Define a reference to an object. More...
#define	DEFINE_FSTR_REF_NAMED(name, ObjectType)   DEFINE_FSTR_REF(name, ObjectType, FSTR_DATA_NAME(name).object);
#define	FSTR_DATA_NAME(name)   __fstr__##name
	Provide internal name for generated flash string structures. More...
#define	FSTR_PTR(objref)   static_cast<std::remove_reference<decltype(objref)>::type*>(&FSTR_DATA_NAME(objref).object)
	Given an Object& reference, return a pointer to the actual object. More...
#define	FSTR_CHECK_STRUCT(name)
	Check structure is POD-compliant and correctly aligned. More...
#define	IMPORT_FSTR_OBJECT(name, ObjectType, file)
	Import an object from an external file with reference. More...
#define	IMPORT_FSTR_OBJECT_LOCAL(name, ObjectType, file)
	Like IMPORT_FSTR_OBJECT except reference is declared static constexpr. More...

Detailed Description

Macro Definition Documentation

DECLARE_FSTR_OBJECT

#define DECLARE_FSTR_OBJECT	(		name,
			ObjectType
	)		extern const ObjectType& name;

Declare a global Object reference.

Parameters

name
ObjectType

DEFINE_FSTR_REF

#define DEFINE_FSTR_REF	(		name,
			ObjectType,
			object
	)		const ObjectType& name PROGMEM = object.template as<ObjectType>();

Define a reference to an object.

Parameters

name	Name for reference
ObjectType	Fully qualified typename of object required, e.g. FSTR::String, FlashString, FSTR::Vector<int>, etc.
object	Object instance to cast

DEFINE_FSTR_REF_NAMED

#define DEFINE_FSTR_REF_NAMED	(		name,
			ObjectType
	)		DEFINE_FSTR_REF(name, ObjectType, FSTR_DATA_NAME(name).object);

FSTR_CHECK_STRUCT

#define FSTR_CHECK_STRUCT

(

name

)

Value:

    static_assert(std::is_pod<decltype(name)>::value, "FSTR structure not POD");                                       \
    static_assert(offsetof(decltype(name), data) == sizeof(uint32_t), "FSTR structure alignment error");

Check structure is POD-compliant and correctly aligned.

FSTR_DATA_NAME

#define FSTR_DATA_NAME

(

name

)

__fstr__##name

Provide internal name for generated flash string structures.

FSTR_PTR

#define FSTR_PTR

(

objref

)

static_cast<std::remove_reference<decltype(objref)>::type*>(&FSTR_DATA_NAME(objref).object)

Given an Object& reference, return a pointer to the actual object.

Parameters

objref

When an Object pointer is required, such when defining entries for a Vector or Map, it is usually sufficient to use &objref.

However, some older compilers such as GCC 4.8.5 requires such references to be declared constexpr. For example, this fails with FSTR structure not POD:

    DEFINE_FSTR(globalStringRef, "This creates a global reference");
    DEFINE_VECTOR(myVector, FSTR::String, &globalStringRef);
                                       ^^^

Global references cannot be declared constexpr, so changing DEFINE_FSTR to DEFINE_FSTR_LOCAL will fix the problem.

Another solution is to get a direct pointer to the actual data structure:

    DEFINE_VECTOR(myVector, FSTR::String, FSTR_PTR(globalStringRef));

We can only do this of course if the data structure is in scope.

IMPORT_FSTR_OBJECT

#define IMPORT_FSTR_OBJECT	(		name,
			ObjectType,
			file
	)

Value:

    IMPORT_FSTR_DATA(FSTR_DATA_NAME(name), file)                                                                       \
    extern "C" __attribute__((visibility("hidden"))) const FSTR::ObjectBase FSTR_DATA_NAME(name);                      \
    DEFINE_FSTR_REF(name, ObjectType, FSTR_DATA_NAME(name));

Import an object from an external file with reference.

Parameters

name	Name for the object
ObjectType	Object type for reference
file	Absolute path to the file containing the content

See also

See also IMPORT_FSTR_DATA

Note

Can only be used at file scope

IMPORT_FSTR_OBJECT_LOCAL

#define IMPORT_FSTR_OBJECT_LOCAL	(		name,
			ObjectType,
			file
	)

Value:

    IMPORT_FSTR_DATA(FSTR_DATA_NAME(name), file)                                                                       \
    extern "C" __attribute__((visibility("hidden"))) const FSTR::ObjectBase FSTR_DATA_NAME(name);                      \
    static constexpr DEFINE_FSTR_REF(name, ObjectType, FSTR_DATA_NAME(name));

Like IMPORT_FSTR_OBJECT except reference is declared static constexpr.