Delphi Data Types for API Integration

Sometime we may need to integrate APIs written on other languages into our Delphi application or we may need to call windows APIs when dealing with complex data structures or we may need to communicate with ActiveX OLE components. Then  in such cases, main issue is Data Type mismatch. So for better compatibility Delphi provides following Pointer data types which can be used to send and receive data to and from other application to Delphi applications.

Integer Data Types

Type	Description	Pointer
Byte	8-bit unsigned integer	PByte
ShortInt	8-bit signed integer	PShortInt
Word	16-bit unsigned integer	PWord
SmallInt	16-bit signed integer	PSmallInt
Cardinal	32-bit unsigned integer	PCardinal
LongWord	32-bit unsigned integer 64-bit unsigned integer	PLongWord
FixedUInt	32-bit unsigned integer	PFixedUInt
Integer	32-bit signed integer	PInteger
LongInt	32-bit signed integer 64-bit signed integer	PLongint
FixedInt	32-bit signed integer	PFixedInt
UInt64	64-bit unsigned integer	PUInt64
Int64	64-bit signed integer	PInt64
NativeUInt	64-bit or 32-bit platform-dependent unsigned integer	PNativeUInt
NativeInt	64-bit or 32-bit platform-dependent signed integer	PNativeInt

Floating-point Data Types

Type	Description	Pointer
Single	Single precision floating-point value (4 bytes)	PSingle
Double	Double precision floating-point value (8 bytes)	PDouble
Extended	Extended precision floating-point value	PExtended

String and Character Data Types

Type	Description	Pointer
AnsiChar	ANSI character	PAnsiChar
Char	Wide character (16-bit)	PChar
WideChar	16-bit character	PWideChar
AnsiString	Represents a dynamically allocated ANSI string whose maximum length is limited only by available memory.	PAnsiString
RawByteString	Use as a "codepage-agnostic" parameter to a method or function, or as a variable type to store BLOB data.	PRawByteString
UnicodeString	Unicode string	PUnicodeString
String	Alias for UnicodeString	PString
ShortString	A string of maximum 255 characters	PShortString
WideString	A string of 16-bit characters	PWideString

Boolean Data Types

Type	Description	Pointer
Boolean	Represents a logical value (true or false).	PBoolean
ByteBool	Represents an 8-bit logical value.
WordBool	Represents a 16-bit logical value.	PWordBool
LongBool	Represents a 32-bit logical value.	PLongBool

Other Data Types

Type	Description	Pointer
Variant	Represents values that can change type at run time.	PVariant
Pointer	Represents a pointer to data of any type.	PPointer
Currency	A fixed-point data type used to hold monetary values.	PCurrency