Delphi Intrinsic Routines

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This topic lists Delphi-only intrinsic routines exposed by the System unit. These intrinsic routines are actually handled by the compiler rather than the run-time library. The table also specifies which compiler support each function

Routine	Description	DCC32	DCC64	DCCOSX64	DCCAARM	DCCIOSARM64	DCCLINUX64	DCCAARM64	DCCOSXARM64	DCCIOSSIMARM64
System.Abs	Returns an absolute value.
System.Addr	Returns a pointer to a specified object.
System.Append	Prepares an existing file for adding text to the end.
System.Assert	Tests whether a Boolean expression is true.
System.Assign	Associates the name of an external file with a file variable.
System.Assigned	Tests for a nil (unassigned) pointer or procedural variable.
System.AssignFile	Associates the name of an external file with a file variable.
System.AtomicCmpExchange	AtomicCmpExchange is used for comparing and exchanging memory values.
System.AtomicDecrement	AtomicDecrement is used for decrementing memory values.
System.AtomicExchange	AtomicExchange is used for exchanging memory values.
System.AtomicIncrement	AtomicIncrement is used for incrementing memory values.
System.BlockRead	Reads one or more records from an open file into a variable.
System.BlockWrite	Writes one or more records from a variable to an open file.
System.Break	Causes the flow of control to exit a for, while, or repeat statement.
System.BuiltInArcTan	Calculates the arctangent of a given number.
System.BuiltInArcTan2	Calculates the arctangent angle and quadrant of a given number.
System.BuiltInCos	Calculates the cosine of an angle.
System.BuiltInLn	Calculates the natural logarithm of a real expression.
System.BuiltInLnXPlus1	Calculates the natural logarithm of (X+1).
System.BuiltInLog10	Calculates log base 10.
System.BuiltInLog2	Calculates log base 2.
System.BuiltInSin	Calculates the sine of the angle.
System.BuiltInSqrt	Calculates the square root of X.
System.BuiltInTan	Calculates the tangent of X.
System.Chr	Returns the character for a specified ASCII value.
System.Close	Terminates the association between a file variable and an external file.
System.CloseFile	Terminates the association between file variable and an external disk file.
System.Concat	Concatenates two or more strings into one.
System.Continue	Allows the flow of control to proceed to the next iteration of for, while, or repeat statements.
System.Copy	Returns a substring of a string or a segment of a dynamic array.
System.Dec	Decrements a variable by 1 or N.
System.Default	Returns the zero representation of type identifier T.
System.Delete	Removes a substring from a string.
System.Dispose	Releases memory allocated for a dynamic variable.
System.Eof	Tests whether the file position is at the end of a file.
System.Eoln	Tests whether the file pointer is at the end of a line.
System.Erase	Deletes an external file.
System.Exclude	Removes an element from a Delphi set.
System.Exit	Exits from the current procedure.
System.Fail	Cancels the construction of an object (Turbo Pascal object model).
System.FilePos	Returns the current file position.
System.FileSize	Returns the number of records in a file.
System.FillChar	Fills contiguous bytes with a specified value.
System.Finalize	Uninitializes a dynamically allocated variable.
System.Flush	Empties the buffer of a text file opened for output.
System.FreeMem	FreeMem frees a memory block.
System.GetDir	Returns the current directory.
System.GetMem	GetMem allocates a memory block.
System.GetTypeKind	Returns the RTTI information for a given type.
System.Halt	Initiates abnormal termination of a program.
System.HasWeakRef	Returns True when the type T is WEAKREF type.
System.Hi	Returns the high-order byte of X as an unsigned value.
System.High	Returns the highest value in the range of an argument.
System.Inc	Increments an ordinal value by one or N.
System.Include	Adds an element to a Delphi set.
System.Initialize	Initializes a dynamically allocated variable.
System.Insert	Inserts a substring into a string beginning at a specified point.
System.IsConstValue	Returns the boolean data type of a value.
System.IsManagedType	Returns true if T is a interface, string or dynamic array, or a record containing such. A class containing a managed type will return false.
System.Length	Returns the number of characters in a string or elements in an array.
System.Lo	Returns the low order Byte of argument X.
System.Low	Returns the lowest value in a range.
System.MemoryBarrier	Enforces an ordering constraint on memory operations.
System.MulDivInt64	Returns the value of this expression: Int64((Int128(AValue) * Int128(AMul)) div Int128(ADiv)).
System.New	Creates a new dynamic variable and sets P to point to it.
System.Odd	Returns true if argument is an odd number.
System.Ord	Returns the ordinal value of an ordinal-type expression.
System.Pi	Returns 3.1415926535897932385.
System.Pred	Returns the predecessor of the argument.
System.Ptr	Converts a specified address to a pointer.
System.Read	Read reads data from a file.
System.Readln	Reads a line of text from a file.
System.ReallocMem	ReallocMem reallocates a memory block.
System.Rename	Changes the name of an external file.
System.Reset	Opens an existing file.
System.ReturnAddress	Returns the return address of the current function execution.
System.Rewrite	Creates a new file and opens it.
System.Round	Returns the value of X rounded to the nearest whole number.
System.RunError	Stops execution and generates a runtime error.
System.Seek	Moves the current position of a file to a specified component.
System.SeekEof	Returns the end-of-file status of a file, ignoring whitespace.
System.SeekEoln	Returns the end-of-line status of a file, ignoring whitespace.
System.SetLength	Sets the length of a string or dynamic-array variable.
System.SetString	Sets the contents and length of the given string.
System.SetTextBuf	Assigns an I/O buffer to a text file.
System.SizeOf	Returns the number of bytes occupied by a variable or type.
System.Slice	Returns a sub-section of an array.
System.Sqr	Returns the square of a number.
System.Str	Formats a string and returns it to a variable.
System.Succ	Returns the successor of an argument.
System.Swap	Exchanges high order byte with the low order byte of an integer or word.
System.Trunc	Truncates a real number to an integer.
System.Truncate	Deletes all the records after the current file position.
System.TypeHandle	Returns the RTTI information for a given type.
System.TypeInfo	Returns the RTTI information for a given type.
System.TypeOf	Deprecated routine.
System.Val	Converts a string to a numeric representation.
System.VarArrayRedim	Resizes a Variant array.
System.VarCast	Converts a variant to specified type.
System.VarClear	Empties a Variant so that it is unassigned.
System.VarCopy	Copies a Variant to another Variant.
System.Write	Writes to either a typed file or a text file.
System.Writeln	Writes to a text file and adds an end-of-line marker.

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