srv_paramlen (Extended Stored Procedure API)

重要提示：
后续版本的 Microsoft SQL Server 将删除该功能。请不要在新的开发工作中使用该功能，并尽快修改当前还在使用该功能的应用程序。 Use CLR integration instead.

Returns the data length of a remote stored procedure call parameter. This function has been superseded by the srv_paraminfo function.

语法

int srv_paramlen (
SRV_PROC *
srvproc
,
int
n 
);

Arguments

• srvproc
  Is a pointer to the SRV_PROC structure that is the handle for a particular client connection (in this case, the handle that received the remote stored procedure call). The structure contains information that the Extended Stored Procedure API library uses to manage communication and data between the application and the client.

• n
  Indicates the number of the parameter. The first parameter is 1.

Returns

The actual length, in bytes, of the parameter data. If there is no nth parameter or there is no remote stored procedure, it returns -1. If the nth parameter is NULL, it returns 0.

This function returns the following values, if the parameter is one of the following Microsoft SQL Server 2005 system data types.

New data types	Input data length
BITN	NULL: 1 ZERO: 1 >=255: N/A <255: N/A
BIGVARCHAR	NULL: 0 ZERO: 1 >=255: 255 <255: actual len
BIGCHAR	NULL: 0 ZERO: 255 >=255: 255 <255: 255
BIGBINARY	NULL: 0 ZERO: 255 >=255: 255 <255: 255
BIGVARBINARY	NULL: 0 ZERO: 1 >=255: 255 <255: actual len
NCHAR	NULL: 0 ZERO: 255 >=255: 255 <255: 255
NVARCHAR	NULL: 0 ZERO: 1 >=255: 255 <255: actual len
NTEXT	NULL: -1 ZERO: -1 >=255: -1 <255: -1

*   actual len = Length of multibyte character string (cch)

备注

Each remote stored procedure parameter has an actual and a maximum data length. For standard fixed-length data types that do not allow null values, the actual and maximum lengths are the same. For variable-length data types, the lengths can vary. For example, a parameter declared as varchar(30) can have data that is only 10 bytes long. The parameter's actual length is 10 and its maximum length is 30. The srv_paramlen function gets the actual data length, in bytes, of a remote stored procedure. To obtain the maximum data length of a parameter, use srv_parammaxlen.

When a remote stored procedure call is made with parameters, the parameters can be passed either by name or by position (unnamed). If the remote stored procedure call is made with some parameters passed by name and some passed by position, an error occurs. The SRV_RPC handler is still called, but it appears as if there were no parameters and srv_rpcparams returns 0.

安全说明：
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.

请参阅

参考

srv_paraminfo (Extended Stored Procedure API)
srv_rpcparams (Extended Stored Procedure API)

帮助和信息

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