Question

我自己教Pro * C，这是一个带有游标的程序，通过数据库中的记录，它编译并运行。它只需提示＆＃34;输入Guest_ID（键入exit to terminate）＆gt;＆gt;＆＃34;。之后它会出现错误，因为＆＃34;分段错误（核心转储）＆＃34;如果输入整数。如果输入一个字符串，它似乎立即进入外部for循环内的条件

if(nGuest_ID==0)
{
      printf("BYE\n");
      exit(0);
}

并打印＆＃34; BYE＆＃34;然后退出。由于我还熟悉如何通过SQL声明和输入变量，因此我不确定哪些声明对于排除故障可能至关重要，所以我在这里完全保留了代码。

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
exec sql include sqlca;

// OK - Here we GO
void main()
{
    // First, create all the variables that we will need to communicate between 
    // the "C" program and the database
    exec sql begin declare section;
        //VARCHAR sLastName[51], sFirstName[51], sHotelName[51], sCheckInDate[12], sRoom[11];
        VARCHAR sLastName[51], sFirstName[51], sHotelName[51], sTransDate[11];
        //int nDays, nGuest_ID, nCount;
        int nGuest_ID, nQuantity, nUnitPrice, nCount, nHotelID, nItemID;
        //VARCHAR sInCity[11];
        VARCHAR sItemName[31], sTaxable[11];
        VARCHAR sUserID[21], sPassword[21];
    exec sql end declare section;
/////// begin needs work ///////
        // Now define the cursor we will use to get all of the charges that the guest incurred at all hotels
    exec sql declare dbGuest cursor for
        Select G.Guest_ID, G.Last_Name, G.First_Name, C.Item_ID, C.Item_Name, C.Quantity, C.Unit_Price, C.Trans_Date, H.Hotel_Name, H.Hotel_ID, SI.Taxable
        From Hotel H, Charge C, Stay S, Guest G, Sales_Item SI Where
        C.Stay_ID=S.Stay_ID And H.Hotel_ID=S.Hotel_ID And G.Guest_ID=S.Guest_ID
            And SI.Item_ID=C.Item_ID
        Group By S.Guest_ID;
//////// end needs work ///////
    // Set up the user-id and password to access my database
    // Because we are using the local database on this server
    // we don't need to use any database location or SID
    strcpy(sUserID.arr,"myusername"); 
    strcpy(sPassword.arr,"mypassword"); 
    sUserID.len=strlen(sUserID.arr);
    sPassword.len=strlen(sPassword.arr);
    exec sql connect :sUserID identified by :sPassword;

    // sqlca.sqlcode is a variable that is set based on the last command sent in to the database
    // a value anything other than zero for what we just did (connect to the database) indicates
    // a error.
    if(sqlca.sqlcode !=0)
       {
        //printf("Sorry, cannot connect to server, pgm aborted %s\n",sqlca.sqlcode); //correction 2/5/14
        printf("Sorry, cannot connect to server, pgm aborted %d\n",sqlca.sqlcode); //change to %d
        exit(1);
       }
    //we made it here, so we were able to open the database correctly
    exec sql SELECT COUNT(*) INTO :nCount FROM Guest;
    printf ("There are %d Guests.\n",nCount);
    for(;;){
        // Read in through stdio the Guest we want to query, then set it up do we can use it
        printf("Enter a Guest_ID(type exit to terminate)>>\n");
        scanf("%d",nGuest_ID);
        //Guest_ID.len= strlen(Guest_ID.arr);
        if(nGuest_ID==0)
        {
            printf("BYE\n");
            exit(0);
        }
        printf("%s %s %s %s %d\n","Charge Summary for:", sFirstName.arr, sLastName.arr, " Guest_ID:", nGuest_ID);
        //printf("I do not work yet (type exit to terminate)>>\n");
                // Open our cursor and begin reading records
        exec sql open dbGuest;
        for(;;)
        {
            //exec sql fetch dbGuest into :nGuest_ID, :sLastName, :sFirstName, :sHotelName, :sCheckInDate, :nDays, :sRoom;
            exec sql fetch dbGuest into :nGuest_ID, :sLastName, :sFirstName, :nItemID, :sItemName, :nQuantity, :nUnitPrice, :sTransDate, :sHotelName, :nHotelID;
            if(sqlca.sqlcode !=0)  // If anything went wrong or we read past eof, stop the loop
            {
                break;
            }
            // Do the crazy stuff to end the C-Strings
            sLastName.arr[sLastName.len] = 0;
            sFirstName.arr[sFirstName.len] = 0;
            sItemName.arr[sItemName.len] = 0;
            sTransDate.arr[sTransDate.len] = 0;
            sHotelName.arr[sHotelName.len] = 0;

            // Print out the information for this guest
            printf("%s %d %s %s \n", "Sales_Item: ", nItemID, " - ", sItemName.arr);
        }
        // close the cursor and end the program
        exec sql close dbGuest ;
    }
    exit(0);
}

我确定我犯了一些简单的错误，但我没有找到任何对搜索有帮助的内容。我在服务器上运行它，并且我没有得到任何调试（这是我迄今为止无法解决的唯一主要错误），所以你拥有的是是）我有的。通常，C程序将在调试器中运行，但这是Pro C，我在整个Oracle Pro C调试事件中丢失了（因为它在远程数据库上运行）。由于这种错误，我通常怀疑没有正确分配内存，但我在这里看不到类似内容。

通过这些但没有帮助：

Segmentation fault (core dumped) runtime error in C

Not so Useful Error -- Segmentation Fault (Core Dump) in Homework Assignment

Segmentation Fault(core dumped)

Segmentation fault (core dumped) read from stdin

Answer 1

由于nGuest_ID是一个int，因此在调用scanf()时，您需要提供nGuest_ID的地址：

scanf("%d",&nGuest_ID);

这可能是您遇到的核心转储的原因，但是，OracleUser提出了一些很好的建议。

希望有所帮助。

Oracle Pro * C - 分段错误（核心转储）

1 个答案: