範例程式碼：初始化和路由程序
本主題包含從動態存取模組接收訊息的原始程式碼大綱， (DMOD) 。
注意
TRACEn () 是用來指定要追蹤資料的宏。 此資料可以包含變數參數。 n 值會識別追蹤的嚴重性層級。 不相符的括弧是刻意的。 它們是由宏的擴充所解決。
/********************************************************************/
/* Sample code for initialization and routing procedure. */
/********************************************************************/
HSEM dummysem = NULL; /* This semaphore is never used */
/********************************************************************/
/* Initialization procedure */
/********************************************************************/
USHORT init_proc()
{
COM_ENTRY("initp");
rc = sbpuinit(&dmodsem, CLIENT, CES3270, username);
TRACE4()"DMOD initialized, rc=%d",rc));
if (rc == NO_ERROR)
{
/********************************************************************/
/* The procedure routproc will be called whenever a message is */
/* received by the DMOD. This is used to post back the application, */
/* but take care to protect any queues against concurrent access by */
/* multiple threads. */
/********************************************************************/
rc = sepdrout(routproc);
TRACE4()"Rout proc set up, rc=%d",rc));
if (rc == NO_ERROR)
{
/* Other initialization here */
}
}
return (rc);
}
/********************************************************************/
/* The routine routproc is called whenever the DMOD receives a */
/* message or a status indication. */
/********************************************************************/
USHORT FAR _loadds routproc(buf, srcl, status)
BUFHDR FAR *buf; /* Buffer that has been received */
USHORT srcl; /* Locality from which buffer was received */
USHORT status; /* Reason for call */
/* CEDINMSG = message received */
/* CEDINLLN = path error occurred (on srcl) */
{
COM_ENTRY("routp"); /* initialize rc=FALSE */
/* Call the DL BASE to handle re-resource */
/* location */
if (!sbpurcvx(&buf, srcl, status))
{
switch (status) {
case CEDINMSG:
if (buf->destp == S3PROD) /* Is the message for us? */
{
/********************************************************************/
/* Process the received message. */
/* */
/* If the message is DATAFMI on the PLU-SLU session, and the */
/* application has requested to use flow control on the */
/* session, then this processing should include: */
/* */
/* - increment number of messages received by the client */
/* - check whether the number received exceeds the threshold */
/* for normally returning credit to the node. If so, check */
/* whether it is OK to return credit (for example, not short of */
/* buffers), and if OK send a status-resource message to */
/* the node to give it credit to send more messages to the */
/* client. */
/********************************************************************/
rc = TRUE;
TRACE2()"Routing proc got message at %p",buf));
}
else
{
TRACE2()"Routing proc did not take message at %p",buf));
}
break;
case CEDINLLN:
TRACE2()"Path error on %d",srcl));
/********************************************************************/
/* Process the path error status. */
/********************************************************************/
break;
}
/********************************************************************/
/* If the message/status cannot be completely processed here, */
/* the application can queue the message and clear a semaphore for the */
/* main thread to continue the processing. */
/********************************************************************/
} else {
rc = TRUE; /* DLBase handled the message on our behalf */<<<<<<<<<<This should be FALSE or Zero
}
/* Returning a value of TRUE indicates that we processed the */
/* event return(rc);
}
Solution:
A possible solution is to remove the else statment altogether.
Copy Code
/********************************************************************/
/* Sample code for initialization and routing procedure. */
/********************************************************************/
HSEM dummysem = NULL; /* This semaphore is never used */
/********************************************************************/
/* Initialization procedure */
/********************************************************************/
USHORT init_proc()
{
COM_ENTRY("initp");
rc = sbpuinit(&dmodsem, CLIENT, CES3270, username);
TRACE4()"DMOD initialized, rc=%d",rc));
if (rc == NO_ERROR)
{
/********************************************************************/
/* The procedure routproc will be called whenever a message is */
/* received by the DMOD. This is used to post back the application, */
/* but take care to protect any queues against concurrent access by */
/* multiple threads. */
/********************************************************************/
rc = sepdrout(routproc);
TRACE4()"Rout proc set up, rc=%d",rc));
if (rc == NO_ERROR)
{
/* Other initialization here */
}
}
return (rc);
}
/********************************************************************/
/* The routine routproc is called whenever the DMOD receives a */
/* message or a status indication. */
/********************************************************************/
USHORT FAR _loadds routproc(buf, srcl, status)
BUFHDR FAR *buf; /* Buffer that has been received */
USHORT srcl; /* Locality from which buffer was received */
USHORT status; /* Reason for call */
/* CEDINMSG = message received */
/* CEDINLLN = path error occurred (on srcl) */
{
COM_ENTRY("routp"); /* initialize rc=FALSE */
/* Call the DL BASE to handle re-resource */
/* location */
if (!sbpurcvx(&buf, srcl, status))
{
switch (status) {
case CEDINMSG:
if (buf->destp == S3PROD) /* Is the message for us? */
{
/********************************************************************/
/* Process the received message. */
/* */
/* If the message is DATAFMI on the PLU-SLU session, and the */
/* application has requested to use flow control on the */
/* session, then this processing should include: */
/* */
/* - increment number of messages received by the client */
/* - check whether the number received exceeds the threshold */
/* for normally returning credit to the node. If so, check */
/* whether it is OK to return credit (for example, not short of */
/* buffers), and if OK send a status-resource message to */
/* the node to give it credit to send more messages to the */
/* client. */
/********************************************************************/
rc = TRUE;
TRACE2()"Routing proc got message at %p",buf));
}
else
{
TRACE2()"Routing proc did not take message at %p",buf));
}
break;
case CEDINLLN:
TRACE2()"Path error on %d",srcl));
/********************************************************************/
/* Process the path error status. */
/********************************************************************/
break;
}
/********************************************************************/
/* If the message/status cannot be completely processed here, */
/* the application can queue the message and clear a semaphore for the */
/* main thread to continue the processing. */
/********************************************************************/
}
/* Returning a value of TRUE indicates that we processed the */
/* event otherwise FALSE means the message was processed by */
/* DL - Base */
return(rc);
}