OpenVMS Source-Code Demos

basic_calling_c_demo1_part1

1000	!=================================================================================================
	! title  : basic_calling_c_demo1_part1.bas
	! author : Neil Rieck	(http://neilrieck.net) (mailto:n.rieck@sympatico.ca)
	! what   : passing data from BASIC to C (and back again)
	! build  : bas  basic_calling_c_demo1_part1
	!	 : cc   basic_calling_c_demo1_part2
	!	 : link /exc=basic_calling_c_demo.exe	-
	!		basic_calling_c_demo1_part1,	-
	!		basic_calling_c_demo1_part2
	! history:
	! ver who when   what
	! --- --- ------ ---------------------------------------------------------------------------------
	! 100 NSR 141107 original effort
	!=================================================================================================
	option type=explicit							!
	!
	external long function basic_calling_c_demo_c1(string by desc,long by ref,word by ref,byte by ref)
	external sub           basic_calling_c_demo_c2(string by desc,long by ref,word by ref,byte by ref)
	external sub           basic_calling_c_demo_c3(string by desc)
	external sub           basic_calling_c_demo_c4(string by desc)
	!
	!	The next bit of crud was done to show that data can be passed
	!	between BASIC + C using global variables is possible (ugh!!)
	!
	common (abc)	byte	gCmn_sanity	,				&
			long    gCmnL		,				&
			word	gCmnW		,				&
			byte	gCmnB		,				&
			word	gCmnStrLen	,				&
			string	gCmnFixed$ = 30	, ! a fixed length string	&
			byte	gCmn_last
	!
	!	global variables (BASIC only)
	!
	declare string	gMain$			,&
		long	gMainL			,&
		word	gMainW			,&
		byte	gMainB			,&
		long	rc			,&
		string	junk$
	!=======================================================
	!	main
	!=======================================================
	main:
	gCmn_last	= 0					! init
	gCmn_sanity	= loc(gCmn_last)-loc(gCmn_sanity)+1	! save the total byte-count
	print "-i-sanity:",gCmn_sanity				!
	gMain$		= "hello"				! init global variables
	gMainL		= 1					!
	gMainW		= 2					!
	gMainB		= 3					!
	gCmnL		= 4					!
	gCmnW		= 5					!
	gCmnB		= 6					!
	junk$		= "fixed length string data"		!
	gCmnFixed$	= junk$					!
	gCmnStrLen	= len(junk$)				!
	!
	print "-i-calling function c1"				!
	rc = basic_calling_c_demo_c1(gMain$,gMainL,gMainW,gMainB)
	print "-i-rc:",rc					!
	print "-i-gCmnL = ",gCmnL				!
	print "-i-gCmnW = ",gCmnW				!
	print "-i-gCmnB = ",gCmnB				!
	!
	print "-i-calling void function c2"			!
	gMain$		= gMain$ + " there"			!
	gMainL		= gMainL + 1				!
	gMainW		= gMainW + 1				!
	gMainB		= gMainB + 1				!
	call basic_calling_c_demo_c2(gMain$,gMainL,gMainW,gMainB)
	print "-i-gCmnL = ",gCmnL				!
	print "-i-gCmnW = ",gCmnW				!
	print "-i-gCmnB = ",gCmnB				!
	!
	print "-i-calling void function c3"			!
	call basic_calling_c_demo_c3(gMain$)			!
	!
	print "-i-calling void function c4"			!
	call basic_calling_c_demo_c4(gMain$)			!
	!
	print "-i-exiting"					!
	end							!

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Neil Rieck
Kitchener - Waterloo - Cambridge, Ontario, Canada.