BRL.Blitz: Globals Functions Modinfo Source  

Blitz runtime

The Blitz runtime module provides low level functionality required by BlitzMax applications when they are running. This includes things like memory management, exception handling and string and array operations.

Much of the functionality provided by this module is hidden from application programmers, but is instead used 'behind the scenes' by the compiler. However, there are some very useful commands for debugging, memory management and simple standard IO.

Globals

Global AppArgs$[]
DescriptionArguments passed to the application at startup.
InformationThe AppArgs global array contains the command line parameters sent to an application when it was started. The first element of AppArgs always contains the name of the application. However, the format of the name may change depending on how the application was launched. Use AppDir or AppFile for consistent information about the applications name or directory.
Example
' appargs.bmx
' print the command line arguments passed to the program at runtime

Print "Number of arguments = "+AppArgs.length

For a$=EachIn AppArgs
Print a$
Next

Global AppDir$
DescriptionApplication directory.
InformationThe AppDir global variable contains the fully qualified directory of the currently executing application. An application's initial current directory is also set to AppDir when an application starts.
Example
' appdir.bmx
' requests the user to select a file from the application's directory

Print "Application Directory="+AppDir$

file$=RequestFile("Select File to Open","",False,AppDir$)

Print "file selected was :"+file

Global AppFile$
DescriptionApplication file name.
InformationThe AppFile global variable contains the fully qualified file name of the currently executing application.
Example
' appfile.bmx

Print "This program's executable is located at "+AppFile$

Global AppTitle$
DescriptionApplication title.
InformationThe AppTitle global variable is used by various commands when a default application title is required - for example, when opening simple windows or requesters.

Initially, AppTitle is set the value "BlitzMax Application". However, you may change AppTitle at any time with a simple assignment.

Global LaunchDir$
DescriptionDirectory from which application was launched.
InformationThe LaunchDir global variable contains the current directory at the time the application was launched. This is mostly of use to command line tools which may need to access the 'shell' current directory as opposed to the application directory.
Example
' launchdir.bmx

Print "This program was launched from "+LaunchDir$

Functions

Function DebugLog( message$ )
DescriptionWrite a string to debug log.
InformationIf there is no debugger present, this command is ignored.

Function DebugStop()
DescriptionStop program execution and enter debugger.
InformationIf there is no debugger present, this command is ignored.

Function Delay( millis )
DescriptionWait for a given number of milliseconds.
InformationDelay suspends program execution for at least millis milliseconds.

A millisecond is one thousandth of a second.

Function GCCollect()
ReturnsThe amount of memory, in bytes, collected.
DescriptionRun garbage collector.

Function GCMemAlloced()
ReturnsThe amount of memory, in bytes, currently allocated by the application.
DescriptionMemory allocated by application.
InformationThis function only returns 'managed memory'. This includes all objects, strings and arrays in use by the application.

Function GCSetMode( mode )
DescriptionSet garbage collector mode.
Informationmode can be one of the following:
1 : automatic GC - memory will be automatically garbage collected
2 : manual GC - no memory will be collected until a call to GCCollect is made
The default GC mode is automatic GC.

Function HandleFromObject( obj:Object )
ReturnsAn integer object handle.
DescriptionConvert object to integer handle.
InformationAfter converting an object to an integer handle, you must later release it using the Release command.

Function HandleToObject:Object( handle )
ReturnsThe object associated with the integer handle.
DescriptionConvert integer handle to object.

Function MemAlloc:Byte Ptr( size )
ReturnsA new block of memory size bytes long.
DescriptionAllocate memory.

Function MemClear( mem:Byte Ptr,size )
DescriptionClear a block of memory to 0.

Function MemCopy( dst:Byte Ptr,src:Byte Ptr,size )
DescriptionCopy a non-overlapping block of memory.

Function MemExtend:Byte Ptr( mem:Byte Ptr,size,new_size )
ReturnsA new block of memory new_size bytes long.
DescriptionExtend a block of memory.
InformationAn existing block of memory specified by mem and size is copied into a new block of memory new_size bytes long. The existing block is released and the new block is returned.

Function MemFree( mem:Byte Ptr )
DescriptionFree allocated memory.
InformationThe memory specified by mem must have been previously allocated by MemAlloc or MemExtend.

Function MemMove( dst:Byte Ptr,src:Byte Ptr,size )
DescriptionCopy a potentially overlapping block of memory.

Function MilliSecs()
ReturnsMilliseconds since computer turned on.
DescriptionGet millisecond counter.
InformationMilliSecs returns the number of milliseconds elapsed since the computer was turned on.

A millisecond is one thousandth of a second.

Function OnEnd( fun() )
DescriptionAdd a function to be called when the program ends.
InformationOnEnd allows you to specify a function to be called when the program ends. OnEnd functions are called in the reverse order to that in which they were added.
Example
' onend.bmx

Function cleanup()
Print "cleaning up"
End Function

OnEnd cleanup
Print "program running"
End	'the cleanup function will be called at this time

Function ReadStdin$()
ReturnsA string read from stdin. The newline terminator, if any, is included in the returned string.
DescriptionRead a string from stdin.

Function RuntimeError( message$ )
DescriptionGenerate a runtime error.
InformationThrows a TRuntimeException.
Example
' runtimeerror.bmx

If a=0 RuntimeError "This program has failed badly."

Function WriteStderr( str$ )
DescriptionWrite a string to stderr.
InformationWrites str to stderr and flushes stderr.

Function WriteStdout( str$ )
DescriptionWrite a string to stdout.
InformationWrites str to stdout and flushes stdout.

Keywords

Keyword Abs
DescriptionNumeric 'absolute value' unary operator.
Example
Rem
Abs is a mathematical operator that performs the Absolute function.
End Rem

For f#=-1 To 1 Step 0.125
	Print "Abs "+f+"="+Abs f
Next

Keyword Abstract
DescriptionDenote a Type or Method as Abstract.
Example
Rem
A BlitzMax type that contains Abstract methods becomes abstract itself.
Abstract types are used to define interfaces that extending types must 
implement before they can be used to create new instances.

In the following code TShape is an abstract type in that you can not
create a TShape but anything extending a TShape must implement a Draw()
method.
End Rem

Type TShape
	Field	xpos,ypos
	Method Draw() Abstract
End Type

Type TCircle extends TShape
	Field	radius
	
	Function Create:TCircle(x,y,r)
		local c:TCircle=new TCircle
		c.xpos=x;c.ypos=y;c.radius=r
		return c
	End Function
	
	Method Draw()
		DrawOval xpos,ypos,radius,radius
	End Method
End Type

Type TRect extends TShape
	Field	width,height
	
	Function Create:TRect(x,y,w,h)
		local r:TRect=new TRect
		r.xpos=x;r.ypos=y;r.width=w;r.height=h
		return r
	End Function
	
	Method Draw()
		DrawRect xpos,ypos,width,height
	End Method
End Type

local 	shapelist:TShape[4]
local	shape:TShape

shapelist[0]=TCircle.Create(200,50,50)
shapelist[1]=TRect.Create(300,50,40,40)
shapelist[2]=TCircle.Create(400,50,50)
shapelist[3]=TRect.Create(200,180,250,20)

graphics 640,480
while not keyhit(KEY_ESCAPE)
	cls
	for shape=eachin shapelist
		shape.draw
	next
	flip
wend
end

Keyword And
DescriptionConditional 'And' binary operator.
Example
Rem
And is a boolean operator that performs the AND function.
End Rem

For i=1 To 10
	If i>3 And i<6 Print "!" Else Print i
Next

Keyword Asc
DescriptionGet character value of the first character of a string.
Example
Rem
Asc returns the unicode value of the first character of a string.
End Rem

print Asc("A")	'65
Print "A"[0]	'65 - equivalent index style implementation

Keyword Assert
DescriptionThrow a RuntimeError if a condition is False.
Example
Rem
Assert generates a BlitzMax runtime error if the specified condition is false.
End Rem

a=LoadImage("nonexistant image file")
Assert a,"Image Failed to Load"

Keyword Byte
DescriptionUnsigned 8 bit integer Type.
Example
Rem
Byte is an unsigned 8 bit integer BlitzMax primitive type.
End Rem

Local a:byte

a=512;print "a="+a	'prints 0
a=-1;print "a="+a	'prints 255

Keyword Case
DescriptionConditional code inside a Select block.
Example
' case.bmx

' Case performs a comparison with the preceeding value(s) and that
' listed in the enclosing Select statement:

a=Int( Input("Enter a number between 1 and 5 ") )

Select a
	Case 1 Print "You think small"
	Case 2 Print "You are even tempered"
	Case 3,4 Print "You are middle of the road"	
	Case 5 Print "You think big"
	Default Print "You are unable to follow instructions"
End Select

Keyword Catch
DescriptionCatch an exception Object in a Try block.
Example
Rem
Catch defines an exception handler following a Try..EndTry Block.
End Rem

Try
	repeat
		a:+1
		print a
		if a>20 throw "chunks"
	forever
Catch a$
	print "caught exception "+a$
EndTry

Keyword Chr
DescriptionCreate a string of length 1 with a character code.
Example
Rem
Chr returns a String of length 1 containing the unicode character of the value.
End Rem

print Chr(65)	'A

Keyword Const
DescriptionDeclare a constant.
Example
Rem
Const defines the preceeding variable declaration as constant.
End Rem

Const ON=TRUE
Const OFF=FALSE

Const TWOPI#=2*PI

print TWOPI

Keyword Continue
DescriptionContinue execution of enclosing loop.
Example
Rem
Continue causes program flow to return to the start of the enclosing While, Repeat or For program loop
End Rem

For i=1 To 20
	If i Mod 2 Continue
	Print i
Next

Keyword Default
DescriptionDefault code inside a Select block.
Example
Rem
Default is used in a Select block to mark a code section that is executed if all prior Case statements fail.
End Rem

a$=Input("What is your favorite color?")
a$=lower(a$)	'make sure the answer is lower case

Select a$
	case "yellow" Print "You a bright and breezy"
	case "blue" Print "You are a typical boy"
	case "pink" Print "You are a typical girl"
	default Print "You are quite unique!"
End Select

Keyword DefData
DescriptionDefine class BASIC style data.
Example
' defdata.bmx

ReadData name$
ReadData age,skill

Print "name="+name+" age="+age+" skill="+skill

DefData "Simon",37,5000

Keyword Delete
DescriptionReserved for future expansion.
Example
Rem
Reserved for future expansions.
End Rem

Keyword Double
Description64 bit floating point Type.
Example
Rem
Double is a 64 bit floating point BlitzMax primitive type.
End Rem

Local speedoflight:Double
Local distance:Double
Local seconds:Double

speedoflight=299792458:Double	'meters per second
distance=149597890000:Double	'average distance in meters from earth sun

seconds=distance/speedoflight

Print "Number of seconds for light to travel from earth to sun="+seconds

Keyword EachIn
DescriptionIterate through an array or collection.
Example
Rem
Specifies a BlitzMax collection type whose values are assigned sequentially to the For iterator.
End Rem

Local a[]=[0,5,12,13,20]

for b=eachin a
	print b
next

Keyword Else
DescriptionElse provides the ability For an If Then construct to execute a second block of code when the If condition is False.
Example
Rem
Else provides the ability for an If Then construct to execute a second block of code when the If condition is false.
End Rem

i=3

If i<5 Print "i<5" Else Print "i>=5"	' single line If Else

If i<5			'block style If Else
	Print "i<5"
Else
	Print "i>=5"
EndIf

Keyword ElseIf
DescriptionElseIf provides the ability to test and execute a section of code if the initial condition failed.
Example
Rem
ElseIf provides the ability to test and execute a section of code if the initial condition failed.
End Rem

age=Int( Input("How old Are You?") )

If age<13
	Print "You are young"
ElseIf age<20
	Print "You are a teen!"
Else
	Print "You are neither young nor a teen"
EndIf

Keyword End
DescriptionEnd program execution.
Example
Rem
The End command causes a program to exit immediately.
End Rem

Print "Hello!"
End
Print "This line will never be printed as the program has already been ended."

Keyword EndExtern
DescriptionEndExtern marks the End of an Extern section.
Example
Rem
EndExtern marks the end of an Extern section.
End Rem

Extern 
	Function puts( str$z )
End Extern

puts "Using clib's put string!"

Keyword EndFunction
DescriptionEnd a Function declaration.
Example
Rem
Function marks the end of a BlitzMax function declaration.
End Rem

Function RandomName$()
	local a$[]=["Bob","Joe","Bill"]
	Return a[Rnd(Len a)]
End Function

For i=1 To 5
	Print RandomName$()
Next

Keyword EndIf
DescriptionMarks the End of an If Then block.
Example
Rem
EndIf marks the end of an If Then block.
End Rem

i=5

If i<10
	Print "i<10"
EndIf

Keyword EndMethod
DescriptionEnd a Method declaration.
Example
Rem
EndMethod marks the end of a BlitzMax Method declaration.
End Rem

Type TPoint
	field	x,y

	Method ToString$()
		return x+","+y
	End Method
End Type

a:TPoint=new TPoint
print a.ToString()

Keyword EndRem
DescriptionEnd a remark block.
Example
Rem
All code between Rem and EndRem is ignored by the BlitzMax compiler.
Print "hello"
End Rem

Print "goodbye"

Keyword EndSelect
DescriptionEnd a Select block.
Example
Rem
EndSelect marks the end of a Select block.
End Rem

SeedRnd MilliSecs()

a=Rand(5)

Select a
	Case 1 Print "one"
	Case 2 Print "two"
	Case 3 Print "three"
	Case 4 Print "four"
	Case 5 Print "five"
	Default Print "Program Error"
End Select

Keyword EndTry
DescriptionEnd declaration of a Try block.
Example
Rem
EndTry
EndTry marks the end of a Try block.
End Rem

Keyword EndType
DescriptionEnd a user defined Type declaration.
Example
Rem
EndType marks the end of a BlitzMax custom type.
End Rem

Type TVector
	Field	x,y,z
End Type

Local a:TVector=new TVector

a.x=10
a.y=20
a.z=30

Keyword EndWhile
DescriptionEnd a While block.

Keyword Exit
DescriptionExit enclosing loop.
Example
Rem
Exit causes program flow to exit the enclosing While, Repeat or Select code section.
End Rem

Repeat
	print n
	n:+1
	If n=5 Exit
Forever

Keyword Extends
DescriptionSpecify user defined Type supertype.
Example
Rem
Extends is used in a BlitzMax Type declaration to derive the Type from a specified base class.
End Rem

Type TShape
	Field	xpos,ypos
	Method Draw() Abstract
End Type

Type TCircle extends TShape
	Field	radius
	
	Function Create:TCircle(x,y,r)
		local c:TCircle=new TCircle
		c.xpos=x;c.ypos=y;c.radius=r
		return c
	End Function
	
	Method Draw()
		DrawOval xpos,ypos,radius,radius
	End Method
End Type

Type TRect extends TShape
	Field	width,height
	
	Function Create:TRect(x,y,w,h)
		local r:TRect=new TRect
		r.xpos=x;r.ypos=y;r.width=w;r.height=h
		return r
	End Function
	
	Method Draw()
		DrawRect xpos,ypos,width,height
	End Method
End Type

local 	shapelist:TShape[4]
local	shape:TShape

shapelist[0]=TCircle.Create(200,50,50)
shapelist[1]=TRect.Create(300,50,40,40)
shapelist[2]=TCircle.Create(400,50,50)
shapelist[3]=TRect.Create(200,180,250,20)

graphics 640,480
while not keyhit(KEY_ESCAPE)
	cls
	for shape=eachin shapelist
		shape.draw
	next
	flip
wend
end

Keyword Extern
DescriptionExtern marks the beginning of an external list of Function declarations.
Example
Rem
Extern marks the beginning of an external list of function declarations.
End Rem

Extern 
	Function puts( str$z )
	Function my_puts( str$z )="puts"
End Extern

puts "Using clib's put string!"
my_puts "Also using clib's put string!"

Keyword False
DescriptionConstant integer of value 0.
Example
Rem
False is a Constant Integer assigned the value 0.
End Rem

Print "False="+False

If False
	Print "This code will never be executed"
Endif

Keyword Field
DescriptionDeclare a Field variable.
Example
Rem
Field is used to declare the member variable(s) of a type.
End Rem

Type TVector
	Field	x,y,z
End Type

Local a:TVector=new TVector

a.x=10
a.y=20
a.z=30

Keyword Final
DescriptionDenote a Type or Method as Final.
Example
Rem
Final stops methods from being redefined in super classes.
End Rem

Type T1
	Method ToString$() Final
		return "T1"
	end method
End Type

Type T2 extends T1
	method ToString$()	'compile time error "Final methods cannot be overridden"
		return "T2"
	end method
End Type

Keyword Float
Description32 bit Floating point Type.
Example
Rem
Float is a 32 bit floating point BlitzMax primitive type.
End Rem

Local a:float

a=1

for i=1 to 8
	print a
	a=a*0.1
next

for i=1 to 8
	a=a*10
	print a
next

Keyword For
DescriptionMarks the start of a loop that uses an iterator to execute a section of code repeatedly.
Example
Rem
For marks the start of a loop that uses an iterator to execute a section of code repeatedly.
End Rem

' print 5 times table

For i=1 to 12
	Print "5*"+i+"="+5*i
Next

Keyword Forever
DescriptionContinue a Repeat block Forever.
Example
Rem
Forever is an alternate ending to a Repeat block that will cause the loop to always repeat.
End Rem

Repeat
	Print i+" Ctrl-C to End!" 
	i:+1
Forever

Keyword Framework
DescriptionFramework builds the BlitzMax application with only the Module specified rather than all modules installed.

Keyword Function
DescriptionBegin a Function declaration.
Example
Rem
Function marks the beginning of a BlitzMax function declaration.

When a function does not return a value the use of brackets when
calling the function is optional.
End Rem

Function NextArg(a$)
	Local	p
	p=instr(a$,",")
	if p 
		NextArg a$[p..]
		print a$[..p-1]
	else
		print a$
	endif
End Function

NextArg("one,two,three,four")

NextArg "22,25,20"	'look ma, no brackets

Keyword Global
DescriptionDeclare a Global variable.
Example
Rem
Global defines a variable as Global allowing it be accessed from within Methods and Functions.
End Rem

Global a=20

Function TestGlobal()
	print "a="+a
End Function

TestGlobal
print "a="+a

Keyword Goto
DescriptionTransfer program flow to specified label.
Example
Rem
Causes program execution to jump to the #label specified.
End Rem

Print "one"
Goto here
Print "two"
#here
Print "three"

Keyword If
DescriptionBegin a conditional block.
Example
Rem
If begins a conditional block.
End Rem

If 3<5 Print "3<5"	'single line if

If 5<7				'if block
	Print "5<7"
EndIf

Keyword Import
DescriptionImport declarations from a Module or source file.
Example
Rem
:Import specifies the external BlitzMax modules and source files used by the program.
End Rem

Framework BRL.GlMax2D

Import BRL.System

Graphics 640,480,32

While Not KeyHit(KEY_ESCAPE)
	Cls
	DrawText "Minimal 2D App!",0,0
	Flip
Wend

Keyword Incbin
DescriptionEmbed a data file.
Example
Rem
IncBin embeds an external data file in a BlitzMax program that can 
then be read using the "incbin::" device name.
End Rem

' code snippet from demos/firepaint/firepaint.bmx

Incbin "stars.png"

Local stars=LoadImage( "incbin::stars.png" )

Keyword IncbinLen
DescriptionGet length of embedded data file.
Example
Rem
IncBinLen returns the size in bytes of the specified embedded binary file.
End Rem

incbin "incbinlen.bmx"

local p:byte ptr=IncBinPtr("incbinlen.bmx")
local bytes=incbinlen("incbinlen.bmx")

local s$=StringFromBytes(p,bytes)

Print "StringFromBytes(p,bytes)="+s$

Keyword IncbinPtr
DescriptionGet start address of embedded data file.
Example
Rem
IncBinPtr returns a byte pointer to the specified embedded binary file.
End Rem

Incbin "incbinptr.bmx"

Local p:Byte Ptr=IncbinPtr("incbinptr.bmx")
Local bytes=IncbinLen("incbinptr.bmx")

Local s$=String.FromBytes(p,bytes)

Print "StringFromBytes(p,bytes)="+s$

Keyword Include
DescriptionInclude effectively 'inserts' the specified file into the file being compiled.

Keyword Inf
DescriptionConstant infinite value.

Keyword Int
DescriptionSigned 32 bit integer Type.
Example
Rem
Int is a signed 32 bit integer BlitzMax primitive type.
End Rem

Local a:Int

' the following values all print 0 as BlitzMax "rounds to zero"
' when converting from floating point to integer

a=0.1;print a
a=0.9;print a
a=-0.1;print a
a=-0.9;print a

Keyword Len
DescriptionNumber of characters in a String or elements in an array.
Example
Rem
Len is a BlitzMax operator that returns the number of elements in a container Type.
End Rem

a$="BlitzMax Rocks"
Print Len a$	'prints 14

Local b[]
Print Len b		'prints 0

b=new Int[20]
Print Len b		'prints 20

Keyword Local
DescriptionDeclare a Local variable.
Example
Rem
Local defines a variable as local to the Method or Function it is defined meaning it is automatically released when the function returns.
End Rem

Function TestLocal()
	Local	a
	a=20
	print "a="+a
	Return
End Function

TestLocal
print "a="+a	'prints 0 or if in Strict mode is an error as a is only local to the TestLocal function

Keyword Long
DescriptionSigned 64 bit integer Type.
Example
Rem
Long is a signed 64 bit integer BlitzMax primitive type.
End Rem

Const MAXLONG:Long=$7fffffffffffffff:Long
Const MINLONG:Long=$8000000000000000:Long

Print "A long can have the maximum value of:"+MAXLONG
Print "A long can have the minimum value of:"+MINLONG

Keyword Max
ReturnsThe larger of the two numeric arguments.
DescriptionNumeric 'maximum' builtin function.

Keyword Method
DescriptionBegin a Method declaration.
Example
Rem
Method marks the beginning of a BlitzMax custom type member function.
End Rem

Type TPoint
	field	x,y

	Method ToString$()
		return x+","+y
	End Method
End Type

a:TPoint=new TPoint
print a.ToString()

Keyword Min
ReturnsThe lesser of the two numeric arguments.
DescriptionNumeric 'minimum' builtin function.

Keyword Mod
DescriptionNumeric 'modulus' or 'remainder' binary operator.
Example
Rem
Mod is a mathematical operator that performs the Modulo function.
End Rem

For i=6 to -6 Step -1
	Print i+" Mod 3="+(i Mod 3)
Next

Keyword Module
DescriptionDeclare Module scope and identifier.
InformationSee the BlitzMax Language Reference for more information on BlitzMax Modules. keyword: "Module"
Example
Rem
The Module keyword advises the BlitzMax program maker BMK to create a code 
module from the source file.
End Rem

Module PUB.Sequencer

ModuleInfo "Framework: Audio Sequencer for use with FreeAudio"
ModuleInfo "Copyright: Blitz Research Ltd"
ModuleInfo "Author: Simon Armstrong"
ModuleInfo "Version: 1.00"

Keyword ModuleInfo
DescriptionDefine Module properties.
Example
Rem
ModuleInfo allows properties such as Author and Copyright to be included in a module file.
End Rem

Module PUB.Sequencer

ModuleInfo "Framework: Audio Sequencer for use with FreeAudio"
ModuleInfo "Copyright: Blitz Research Ltd"
ModuleInfo "Author: Simon Armstrong"
ModuleInfo "Version: 1.00"

Keyword Nan
DescriptionConstant 'not a number' value.

Keyword New
DescriptionCreate an instance of a user defined Type.
Example
Rem
New creates a BlitzMax variable of the Type specified.
End Rem

Type MyType
	Field	a,b,c
End Type

Local t:MyType
t=New MyType
t.a=20

print t.a

' if a new method is defined for the type it will also be called

Type MyClass
	Field	a,b,c
	Method New()
		print "Constructor invoked!"
		a=10
	End Method
End Type

Local c:MyClass
c=new MyClass
print c.a

Keyword Next
DescriptionEnd a For block.
Example
Rem
Marks the end of a For section.
End Rem

For i=1 to 5;print i;Next

Keyword Not
DescriptionConditional 'Not' binary operator.
Example
Rem
Not is a boolean unary operator that performs the NOT function.
End Rem

Print Not 0			'prints 1 (TRUE)
Print Not 20		'prints 0 (FALSE)

Keyword Null
DescriptionGet Default Null value.
Example
Rem
Null is a BlitzMax Constant representing an empty Object reference.
End Rem

Type mytype
	Field	atypevariable
End Type

Global a:mytype

if a=null Print "a is uninitialized"
a=new mytype
if a<>null Print "a is initialized"

Keyword Object
DescriptionObject Type.
Example
Rem
Object is the base class of all BlitzMax types.

The following function attempts to cast from any object to
the custom type TImage and returns true if the given object
is an instance of TImage or an instance of a &Type derived
from TImage.
End Rem

Function IsImage(obj:Object)
	If TImage(obj) return True
	Return False
End Function

Keyword Or
DescriptionConditional 'Or' binary operator.
Example
Rem
Or is a boolean operator that performs the OR function.
End Rem

For i=1 To 5
	If i=2 Or i=4 Print "!" Else Print i
Next

Keyword Pi
DescriptionConstant Pi value: 3.1415926535897932384626433832795.
Example
Rem
Pi is a Constant Double assigned the value 3.1415926535897932384626433832795
End Rem

Print "Pi="+Pi

Keyword Private
DescriptionPrivate makes a Constant, Global variable or Function only accessible from within the current source file.
Example
Rem
Private makes a variable, function or method only accessible from within the 
current source file.
End Rem

Public

Global	Score,Lives,Health

Private

Global	posx,posy,posz

Keyword Ptr
DescriptionComposite Type specifier for pointer types.
Example
Rem
Ptr is a composite type containing a pointer to a variable of the specified Type.
End Rem

' the following illustrates the use of traditional c style pointers

Local c[]=[1,2,3,4]
Local p:Int Ptr

p=c
Print "pointer 'p' points to:"+p[0]	'1

p:+1
Print "pointer 'p' points to:"+p[0]	'2

p:+1
Print "pointer 'p' points to:"+p[0]	'3

p:+1
Print "pointer 'p' points to:"+p[0]	'4

Keyword Public
DescriptionPublic makes a Constant, Global variable or Function accessible from outside the current source file (Default)
Example
Rem
Public makes a variable, function or method accessible from outside the current source file (default).
End Rem

Public

Global	Score,Lives,Health

Private

Global	posx,posy,posz

Keyword ReadData
DescriptionRead classic BASIC style data.

Keyword Release
DescriptionRelease an integer Object handle.
Example
Rem
Release removes the internal reference caused by creating an integer handle to a type.
End Rem

Type MyType
	field	bigmap[1024*1024]
End Type

a=new MyType
print MemAlloced()

Release a
GCCollect
print MemAlloced()
print a

b:MyType=new MyType
print MemAlloced()

Release b
GCCollect
Print MemAlloced()

Keyword Rem
DescriptionBegin a remark block.
Example
Rem

My Rem Example
First created 9th August, 2004

(C)2050 Blitz Intergalactic Software Corporation

End Rem

Print "This program has no useful function"

Rem

Remarks are useful for making your program easily readable.
You can leave details explaining the function of your program
in a remarks section so that you and any other programmers
that work with your code can more easily understand the workings
of your program

End Rem

Print "Sorry."
End

Keyword Repeat
DescriptionExecute a block of code Until a termination condition is met, or Forever.
Example
Rem
Repeat executes the following section of code until a terminating condition is true.
End Rem

Repeat
	print i
	i:+1
Until i=5

Keyword RestoreData
DescriptionRestore classic BASIC style data.
Example
' restoredata.bmx

For i=1 To 5
	RestoreData mydata	'reset the data pointer everly loop so we don't read past the end
	ReadData name$,age,skill
	Print "name="+name+" age="+age+" skill="+skill
Next

#mydata	'program label that can be used with the RestoreData command

DefData "Simon",37,5000

Keyword Return
DescriptionReturn from a Function.
Example
Rem
Return exits a BlitzMax function or method with an optional value.
The type of return value is dictated by the type of the function.
End Rem

Function CrossProduct#(x0#,y0#,z0#,x1#,y1#,z1#)
	Return x0*x1+y0*y1+z0*z1
End Function

Print "(0,1,2)x(2,3,4)="+CrossProduct(0,1,2,2,3,4)

Function LongRand:long()
	Return (rand($80000000,$7fffffff) shl 32)|(rand($80000000,$7fffffff))
End Function

Print "LongRand()="+LongRand()
Print "LongRand()="+LongRand()

Keyword Sar
DescriptionBitwise 'Shift arithmetic right' binary operator.
Example
Rem
Sar is a binary operator that performs the arithmetic shift to right function.
End Rem

b=$f0f0f0f0
for i=1 to 32
	print bin(b)
	b=b sar 1
next

Keyword Select
DescriptionBegin a Select block.
Example
Rem
Select begins a block featuring a sequence of multiple comparisons with a single value.
End Rem

a=Int( Input("Enter Your Country Code ") )

Select a
	Case 1
		Print "You are from America"
	Case 44
		Print "You are from the United Kingdom"
	Case 62
		Print "You are from Australia"
	Case 64
		Print "You are from New Zealand"
	Default
		Print "I cannot tell which country you are from"
End Select

Keyword Self
DescriptionReference to this Method's Object instance.
Example
Rem
Self is used in BlitzMax Methods to reference the invoking variable.
End Rem

Type MyClass
	Global	count	
	Field	id
	
	Method new()
		id=count
		count:+1
		ClassList.AddLast(self)	'adds this new instance to a global list		
	End Method
End Type

Global ClassList:TList

classlist=new TList

local c:MyClass

c=new MyClass
c=new MyClass
c=new MyClass

for c=eachin ClassList
	print c.id
next

Keyword Sgn
DescriptionNumeric 'sign' unary operator.
Example
Rem
Sgn is a mathematical operator that returns the sign of a value.
End Rem

Print Sgn 50	'1
Print Sgn 0		'0
Print Sgn -50	'-1

Keyword Shl
DescriptionBitwise 'Shift left' binary operator.
Example
Rem
Shl is a binary operator that performs the shift to left function.
End Rem

b=1
for i=1 to 32
	print bin(b)
	b=b shl 1
next

Keyword Short
DescriptionUnsigned 16 bit integer Type.
Example
Rem
Short is an unsigned 16 bit integer BlitzMax primitive type.
End Rem

Local a:short

a=65536;print "a="+a	'prints 0
a=-1;print "a="+a	'prints 65535

Keyword Shr
DescriptionBitwise 'Shift right' binary operator.
Example
Rem
Shr is a binary operator that performs the shift to right function.
End Rem

b=-1
for i=1 to 32
	print bin(b)
	b=b shr 1
next

Keyword SizeOf
DescriptionSize, in bytes, occupied by a variable, string, array or object.
Example
Rem
SizeOf returns the number of bytes of system memory used to store the variable.
End Rem

Type MyType
	Field a,b,c
End Type

Local t:MyType
print sizeof t	'prints 12

Local f!
print sizeof f	'prints 8

Local i
print sizeof i	'prints 4

Local b:Byte
print sizeof b	'prints 1

a$="Hello World"
print sizeof a	'prints 22 (unicode characters take 2 bytes each)

Keyword Step
DescriptionSpecifies an optional constant that is used to increment the For iterator.
Example
Rem
Specifies an optional constant that is used to increment the For iterator.
End Rem

' count backwards from 10 to 0

For i=10 to 0 step -1
	Print i
Next

Keyword Strict
DescriptionSet strict mode.
InformationSee the BlitzMax Language Reference for more information on Strict mode programming. keyword: "Strict"
Example
Rem
Strict advises the BlitzMax compiler to report as errors all auto defined variables.
End Rem

Strict

local a=10

b=20	'compiler error, strict mode means variables must be declared b4 use

Keyword String
DescriptionString Type.
Example
Rem
String is a BlitzMax container type containing a sequence of unicode characters.
End Rem

quote:String=Chr(34)
Print quote+"Hello World!"+quote

Keyword Super
DescriptionReference to the Super Type Object instance.
Example
Rem
Super evaluates to Self cast to the method's immediate base class.
End Rem

Type TypeA
	Method Report()
		print "TypeA reporting"
	End Method
End Type

Type TypeB extends TypeA
	Method Report()
		Print "TypeB Reporting"
		super.Report()
	End Method
End Type

b:TypeB=new TypeB
b.Report()

Keyword SuperStrict
DescriptionSet SuperStrict mode.

Keyword Then
DescriptionOptional separator between the condition and associated code in an If statement.
Example
Rem
Then is an optional separator between the condition and the block of code following an If statement.
End Rem

If 3<5 Then Print "3<5"

Keyword Throw
DescriptionThrow an exception Object to the enclosing Try block.
Example
Rem
Throw generates a BlitzMax exception.
End Rem

Try
	repeat
		a:+1
		print a
		if a>20 throw "chunks"
	forever
Catch a$
	print "caught exception "+a$
EndTry

Keyword To
DescriptionFollowed by a constant which is used to calculate when to exit a For..Next loop.
Example
Rem
Followed by a constant which is used to calculate when to exit a For..Next loop.
End Rem

For i=1 To 5
	print i
Next

Keyword True
DescriptionConstant integer of value 1.
Example
Rem
True is a Constant Integer assigned the value 1.
End Rem

Print "True="+True

If True
	Print "This line will always be executed"
EndIf

If Not True
	Print "This line will never be executed"
EndIf

Keyword Try
DescriptionBegin declaration of a Try block.
Example
Rem
Begin declaration of a Try block.
End Rem

Try
	repeat
		a:+1
		print a
		if a>20 throw "chunks"
	forever
Catch a$
	print "caught exception "+a$
EndTry

Keyword Type
DescriptionBegin a user defined Type declaration.
Example
Rem
Type marks the beginning of a BlitzMax custom type.

Standard BlitzMax types use a preceeding "T" naming
convention to differentiate themselves from standard
BlitzMax variable names.
End Rem

Type TVector
	Field	x,y,z
End Type

Local a:TVector=new TVector

a.x=10
a.y=20
a.z=30

Keyword Until
DescriptionConditionally continue a Repeat block.
Example
Rem
Until marks the end of a Repeat block and is followed by a terminating condition.
End Rem

i=2
Repeat
	print i
	i:*2
Until i>1000000

Keyword Var
DescriptionComposite Type specifier for 'by reference' types.
Example
Rem
Var is a composite type containing a reference to a variable of the 
specified Type.
End Rem

' the following illustrates parsing function parameters by reference

Function ReturnMultiplevalues(a Var,b Var,c Var)
	a=10
	b=20
	c=30
	Return
End Function

Local x,y,z

ReturnMultipleValues(x,y,z)

Print "x="+x	'10
Print "y="+y	'20
Print "z="+z	'30

Keyword Varptr
DescriptionFind the address of a variable.
Example
Rem
Varptr returns the address of a variable in system memory.
End Rem

Local a:int
Local p:int ptr

a=20
p=varptr a
print p[0]

Keyword Wend
DescriptionEnd a While block.
Example
Rem
Wend marks the end of a While section.
End Rem

While i<5
	print i
	i:+1
Wend

Keyword While
DescriptionExecute a block of code While a condition is True.
Example
Rem
While executes the following section of code repeatedly while a given condition is true.
End Rem

Graphics 640,480
While Not KeyHit(KEY_ESCAPE)	'loop until escape key is pressed
	Cls
	For i=1 to 200
		DrawLine rnd(640),rnd(480),rnd(640),rnd(480)
	Next
	Flip
Wend

Module Information

Version1.10
AuthorMark Sibly
LicenseBlitz Shared Source Code
CopyrightBlitz Research Ltd
ModserverBRL
History1.10 Release
HistoryAdded Nan and Inf keyword docs
History1.09 Release
HistoryBCC extern CString fix
History1.08 Release
HistoryRemoved printf from 'Throw'
History1.07 Release
HistoryAdded AppTitle$ global var
History1.06 Release
HistoryRestored ReadData
History1.05 Release
HistoryLotsa little tidyups
History1.04 Release
HistoryFixed C Compiler warnings