Oracle Pro*C -- Segmentation fault (core dumped) - sql

Question

I'm teaching myself Pro*C and this is a program with a cursor through records in a database, and it compiles and runs. It gets as a far as prompting "Enter a Guest_ID(type exit to terminate)>>". After that it errors as "Segmentation fault (core dumped)" if an integer is entered. If a string is entered, it seems to go into the conditional immediately inside the outer for loop at
if(nGuest_ID==0)
{
printf("BYE\n");
exit(0);
}
and prints "BYE" then exits. Since I'm still getting familiar with how variables are declared and fed in from SQL, I wasn't sure what declarations might be crucial for troubleshooting here so I'm leaving the code largely intact here.
#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);
}
I'm sure I'm making some simple mistake but I didn't find anything helpful on search. I'm running this on a server, and I'm not getting any debugging back (this is the only major bug I haven't been able to solve up to this point), so what you have is what I have. Normally C programs would be run in debuggers but this is ProC and I'm kind of lost with the whole Oracle ProC debugging thing (since it's running on a remote database). With this kind of error I'd usually suspect not allocating memory properly, but I don't see anything like that here.
Went through these but not helpful:
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

Since nGuest_ID is an int, when calling scanf(), you'll need to provide address of nGuest_ID:
scanf("%d",&nGuest_ID);
That's the likely cause of the core dump you're experiencing, but, also, OracleUser made some excellent suggestions.
Hope that helps.