Converting From ASCII-EBCDIC Using CPICs CMCNVI and CMCNVO

ID: Q188689

The information in this article applies to:

Microsoft SNA Server, versions 3.0, 3.0SP1, 3.0SP2, 3.0SP3, 4.0, 4.0SP1

SYMPTOMS

SNA Server's CPIC libraries now provide data conversion support through the use of two new CPIC function calls.

Convert_Outgoing (CMCNVO) - The Convert_Outgoing() call is designed to translate text strings from ASCII to EBCDIC and is issued before sending data to a computer that uses EBCDIC encoding (for example, the host).

Convert_Incoming (CMCNVI) - The Convert_Incoming() is designed to translate text strings from EBCDIC to ASCII and is typically issued after receiving data from a computer that uses EBCDIC encoding.

NOTE: These function calls do not take a conversation ID as input and can therefore, be used even if an active conversation does not exist.

RESOLUTION

SNA Server 3.0

To resolve this problem, obtain the latest service pack for SNA Server version 3.0. For additional information, please see the following article in the Microsoft Knowledge Base:

Q184307 How to Obtain the Latest SNA Server Version 3.0 Service Pack

SNA Server 4.0

To resolve this problem, obtain the latest service pack for SNA Server version 4.0. For additional information, please see the following article in the Microsoft Knowledge Base:

Q215838 How to Obtain SNA Server Version 4.0 U.S Service Pack 2

STATUS

Microsoft has confirmed this to be a problem in SNA Server 3.0, 3.0 SP 1, 3.0 SP 2, 3.0 SP 3, 4.0, 4.0 SP 1. This problem was first corrected in SNA Server 3.0 Service Pack 4.

MORE INFORMATION

The function call definitions for CMCNVO and CMCNVI are listed below.

Convert_Incoming()

The Convert_Incoming call (function name cmcnvi) converts a string of EBCDIC characters into ASCII.

NOTE: The return conversion can be performed using Convert_Outgoing.


CM_ENTRY Convert_Incoming(
  unsigned char FAR *string,
  CM_INT32 FAR *string_length,
  CM_INT32 FAR *return_code
);

Parameters

string

Supplied parameter. Specifies the EBCDIC string to be converted. It may contain any of the following characters:


   Uppercase A-Z, lowercase a-z, 0-9, the period (.) and space
   characters, and the special characters < > + - ( ) &
   * ; : , ' ? / _ = ". 

   string_length characters of this string will be replaced by ASCII    equivalents.

string_length

Supplied parameter. Specifies the number of characters to be converted (1 - 32767).

return_code

The code returned from this call. The valid return codes are listed below.

Return Codes:

CM_OK Primary return code; the call executed successfully, the string parameter now contains the converted ASCII string.

CM_PROGRAM_PARAMETER_CHECK Primary return code; the string_length parameter specified an invalid value.

CM_PRODUCT_SPECIFIC_ERROR Primary return code; a product-specific error occurred and has been logged in the product's error log.

State Changes:

The conversation can be in any state. There is no state change.

Remarks:

When data is being received in buffer format in a basic conversation the data buffer may contain multiple logical records; each consisting of a two- byte length field (NN), followed by the data. The application must extract and convert each data string separately (not including the NN bytes). It must not attempt to convert the whole buffer in one operation, because this will make the NN values invalid.

Convert_Outgoing()

The Convert_Outgoing call (function name cmcnvo) converts a string of ASCII characters into EBCDIC.

NOTE: The return conversion can be performed using Convert_Incoming.


CM_ENTRY Convert_Outgoing(
  unsigned char FAR *string,
  CM_INT32 FAR *string_length,
  CM_INT32 FAR *return_code
);

Parameters:

string - Supplied parameter. Specifies the ASCII string to be converted. It may contain any of the following characters:


   Uppercase A-Z, lowercase a-z, 0-9, the period (.) and space
   characters, and the special characters < > + - ( ) & * ; : , '  ?
   / _= ".

   string_length characters of this string will be replaced by EBCDIC 
   equivalents.

string_length - Supplied parameter. Specifies the number of characters to be converted (1 - 32767).

return_code - The code returned from this call. The valid return codes are listed below.

Return Codes:

CM_OK Primary return code; the call executed successfully, the string parameter now contains the converted EBCDIC string.

CM_PROGRAM_PARAMETER_CHECK Primary return code; the string_length parameter specified an invalid value.

CM_PRODUCT_SPECIFIC_ERROR Primary return code; a product-specific error occurred and has been logged in the product's error log.

State Changes:

The conversation can be in any state. There is no state change.

Remarks:

When data is being received in buffer format in a basic conversation the data buffer may contain multiple logical records; each consisting of a two- byte length field (NN), followed by the data. The application must extract and convert each data string separately (not including the NN bytes). It must not attempt to convert the whole buffer in one operation, because this will make the NN values invalid.

For more information concerning character conversion support, please see the following Microsoft Knowledge Base article:

Q139114 SNA Server Support for ASCII-EBCDIC Character Conversion

Additional query words: ebcdic ascii convert conversion CPI-c appc

Keywords :
Version : WINDOWS:3.0,3.0SP1,3.0SP2,3.0SP3,4.0,4.0SP1
Platform : WINDOWS
Issue type : kbbug