---
title: "srv_setcollen (Extended Stored Procedure API) | Microsoft Docs"
ms.custom: ""
ms.date: "03/03/2017"
ms.prod: sql
ms.prod_service: "database-engine"
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ms.technology: stored-procedures
ms.topic: "reference"
apiname: 
  - "srv_setcollen"
apilocation: 
  - "opends60.dll"
apitype: "DLLExport"
dev_langs: 
  - "C++"
helpviewer_keywords: 
  - "srv_setcollen"
ms.assetid: 3c60f1c3-4562-463a-a259-12df172788bd
author: "rothja"
ms.author: "jroth"
---
# srv_setcollen (Extended Stored Procedure API)
[!INCLUDE[appliesto-ss-xxxx-xxxx-xxx-md](../../includes/appliesto-ss-xxxx-xxxx-xxx-md.md)]
    
> [!IMPORTANT]  
>  [!INCLUDE[ssNoteDepFutureDontUse](../../includes/ssnotedepfuturedontuse-md.md)] Use CLR integration instead.  
  
 Specifies the current data length in bytes of a variable-length column or a column that allows NULL values.  
  
## Syntax  
  
```  
  
int srv_setcollen (  
SRV_PROC *  
srvproc  
,  
int   
column  
,  
int  
len   
);  
```  
  
## Arguments  
 *srvproc*  
 Is a pointer to the SRV_PROC structure that is the handle for a particular client connection. The structure contains information the Extended Stored Procedure API library uses to manage communication and data between the application and the client.  
  
 *column*  
 Indicates the number of the column for which the data length is being specified. Columns are numbered beginning with 1.  
  
 *len*  
 Indicates the length, in bytes, of the column data. A length of 0 means the column data value is null.  
  
## Returns  
 SUCCEED or FAIL.  
  
## Remarks  
 Each column of the row must first be defined with **srv_describe**. The column data length is set by the last call to **srv_describe** or **srv_setcollen**. If variable-length data (null-terminated data) changes for a row, **srv_setcollen** must be used to set it to the new length before calling **srv_sendrow**. For a column that allows null values, **srv_describe** must have been called with *desttype* set to a data type that allows nulls (like SRVINTN) and null data is specified by calling **srv_setcollen** with *len* set to 0. Zero length data cannot be specified using the Extended Stored Procedure API.  
  
 Note that when the data type of the column is variable-length, *len* is not checked. This function returns FAIL if called for a fixed-length column.  
  
> [!IMPORTANT]  
>  You should thoroughly review the source code of extended stored procedures, and you should test the compiled DLLs before you install them on a production server. For information about security review and testing, see this [Microsoft Web site](https://go.microsoft.com/fwlink/?LinkID=54761&clcid=0x409https://msdn.microsoft.com/security/).  
  
## See Also  
 [srv_describe (Extended Stored Procedure API)](../../relational-databases/extended-stored-procedures-reference/srv-describe-extended-stored-procedure-api.md)