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|  | **#RUNDLL(** //library, procedure //[,// parameter //] **) **[, | **| RETAIN** **| **] | [,** PASCAL** ] [,** WIN32** ] |
|  |  | **| RELEASE |** |  |

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| **#RUNDLL** | Executes a procedure from any Windows-standard Dynamic Link Library (.DLL). |
| //library// | A string constant containing the name of the .DLL file, including the extension. |
| //procedure// | A string constant containing the name of the procedure in the DLL file to execute. |
| //parameter// | A string constant or expression containing a single parameter to pass to the //procedure//. |
| **RETAIN** | Specifies that the //library// stays in memory after the //procedure// has completed execution. |
| **RELEASE** | Specifies that the //library// is unloaded from memory after the //procedure// has completed execution. |
| **PASCAL** | Specifies that the address only of a parameter string is passed. |
| **WIN32** | Specifies that the //library //is a 32-bit DLL. Deprecated and ignored if present in Clarion 7 versions or higher. |

The **#RUNDLL** statement executes the specified //procedure// from the specified //library//. The //library// .DLL is dynamically loaded before the //procedure// executes and unloaded after, unless the RETAIN attribute is specified.

If the RETAIN attribute is specified, another #RUNDLL statement with the RELEASE attribute and naming the same //library// must follow so that the .DLL is unloaded from memory. Failure to unload the .DLL can result in memory leaks. The RETAIN and RELEASE attributes can be nested as long as the #RUNDLL statements match up.

If a //parameter// is named, then the //procedure// must accept a single *CSTRING parameter (only). If no //parameter// is named, then the //procedure// must not accept any parameters. In either case, the //procedure// cannot return a value. If the //parameter// named is a single-valued user-defined symbol, then any changes to the passed parameter's value in the called //procedure// are reflected in that //parameter// symbol. If the called function changes the value of the passed string, the new value cannot exceed 10000 characters (including the terminating '<;0>').

**Example:**

**!A .DLL 'Services.DLL' contains these two procedures:**

**SoundBeep PROCEDURE**

** CODE**

** BEEP**

**AskForName PROCEDURE(*CSTRING Name)**

**Window  WINDOW('Enter Name),AT(,,260,100),SYSTEM,GRAY,AUTO**

**         ENTRY(@s20),AT(4,4),USE(Name)**

**         BUTTON('OK'),AT(200,4),USE(?Ok),STD(STD:Close)**

**        END**

** CODE**

** OPEN(Window)**

** ACCEPT**

** END**

**! The Template code that calls the procedures in Services.DLL:**

**#DECLARE (%UserName)**

**#SET (%UserName, 'Unknown')**

**#RUNDLL**** ('Services.DLL', 'SoundBeep'),RETAIN       !Use RETAIN to improve performance**

**#RUNDLL**** ('Services.DLL', 'AskForName', %UserName)**

**#RUNDLL**** ('Services.DLL', 'SoundBeep'),RELEASE      !RELEASE matches the RETAIN**