DLL: Run-Time Dynamic Linking

HicEst is an interpreted language and as such has its limitations. When a HicEst solution falls short of your needs, coding critical program parts in a DLL may be of advantage. DLLs can be compiled from most languages.
Frequently the use of DLLs with HicEst is because existing programs lack a graphical user interface.
DLLs are called from HicEst according to Microsoft specifications (STDCALL).
Windows APIs can be called directly from the script. Documentation is found on msdn.microsoft.com
- [error] = DLL( Module=DLLname, Procedure=pName [, Options=..,] [, ErrIf=...] [, ErrIfNot=...] [ERror=label]
- Many DLLs need a compiler-specific runtime-library. If not found a "module not found" message is issued.

Example:
get_memory_status
Call Windows API "GlobalMemoryStatusEx" in Kernel32.dll.
Windows writes the result to a structure ("Mem") with 8 longlong integers (8 byte each).
- CHARACTER Mem*100 ! string Mem is the container for the 8 integers
- Mem = STRUCT(Bytes=memLen, i4U=memLoad, i8=totalPhys, i8=AvailPhys, i8=TotalPageFile, i8=AvailPageFile, i8=TotalVirtual, i8=AvailVirtual, i8=AvailExVirtual)
memLen is now set to 64, TotalPhys, AvailPhys etc are stored as 8-byte binary integers in string Mem
- DLL( Procedure='GlobalMemoryStatusEx', STrucP=Mem, Module='Kernel32.dll', ErrIf=0 ) ! Windows API call
Member 2 of Mem (memLoad, i4U unsigned 4-byte-integer-VALUE) is set to e.g. 18 (%)
- WRITE(Msgbox, Name) Mem ! display structure Mem in message box
e.g. Mem.memLoad=18; Mem.totalPhys=2,096,603,136"; ...

keyword	type	Keywords controlling the DLL call, arbitrary position:
Module	txt	M="c:\DLLs\myDLL" (REQUIRED)
Procedure	txt	P='myfunction' (REQUIRED). Case sensitive.
Unload	num	U=0 to keep the module open for further calls. Default is 1.
ErrIf	num	EI=n calls and displays API GetLastError if API returns n
ErrIfNot	num	EIN=m calls and displays API GetLastError API return is not m
ERror	lbl	ER=999 on error jump to label 999

option	type	Pointers can return output and are required for strings and arrays. Executed in sequence without extra alignments.
I1P	num	4-byte-pointer to signed 1-byte-integer
I2P	num	4-byte-pointer to signed 2-byte-integer
I4P	num	4-byte-pointer to signed 4-byte-integer
I8P	num	4-byte-pointer to signed 8-byte-integer
I1UP	num	4-byte-pointer to unsigned 1-byte-integer
I2UP	num	4-byte-pointer to unsigned 2-byte-integer
I4UP	num	4-byte-pointer to unsigned 4-byte-integer
R4	num	value of 4-byte-floating
R4P	num	4-byte-pointer to 4-byte-floating
R8P	num	4-byte-pointer to 8-byte-floating
CHarP	txt	4-byte-pointer to character string
CHar0P	txt	4-byte-pointer to character string, last byte set by DLL to CHAR(0)
STrucP	txt	4-byte-pointer to structure txt defined by STRUCT before.

option	type	Values do not return output except if embedded in structures, Executed in sequence without extra alignments.
I1	num	value of signed 1-byte-integer
I2	num	value of signed 2-byte-integer
I4	num	value of signed 4-byte-integer
I1U	num	value of unsigned 1-byte-integer
I2U	num	value of unsigned 2-byte-integer
I4U	num	value of unsigned 4-byte-integer

option	type	May be useful for some operations
HINSTance	num	HINST=instance, Module and Procedure options not needed
Wdw1	num	W1=handle to script window, , Module and Procedure options not needed