WRAPTRACE() - Long String Debugging Macro

I kept running into situations where, during debugging, I needed to view the contents of long strings. None of the features available in VC++ were satisfactory. The onscreen, expression, hover feature only displays one screen-width line of the variable's contents. Also, even though an AfxMessageBox() can display thousands of characters, it doesn't have scroll bars and is therefore limited to a viewing area of one screen (about 4,200 characters). In addition, you cannot capture text from an AfxMessageBox(). Finally, MFC's TRACE() debug maco is limited to dumping a maximum of 512 characters to the output window.

To provide a solution to this problem, I wrote the WRAPTRACE() macro. This handly little debugging tool breaks down a long string into 80 character, or shorter, lines of text for display in Developer Studio's output window. Like TRACE(), it is only available during debug. However, unlike TRACE(), the output from WRAPTRACE() is imited only by the 32k size barrier of the CString class.

The source compiles and runs fine on VC++ 5.0.

CODE EXAMPLE:

CString strString = "A businessman walked into a New"
"York City bank and asked for the loan officer. He said he was going to Europe on business"
"for two weeks and needed to borrow $5,000. The loan officer said the bank would need some"
"security for such a loan. The business man then handed over the keys to a Rolls Royce that"
"was parked on the street in front of the bank. Everything checked out and the loan officer"
"accepted the car as collateral for the loan. An employee then drove the Rolls into the"
"bank's underground garage and parked it there. Two weeks later the businessman returned,"
"repaid the $5,000 plus the interest, which came to $15.41. The loan officer said,"
"\"We do appreciate your business and this transaction has worked out very nicely, but"
"we are a bit puzzled. While you were away we checked and found that you are a"
"multimillionaire. What puzzles us is why you would bother to borrow $5,000?\" The"
"business man replied: \"Where else in New York City, can I park my car securely for 2"
"weeks for only 15 bucks?\"";
WRAPTRACE(strString);
OUTPUT WINDOW TEXT:

A businessman walked into a New York City bank and asked for the
loan officer.
He said he was going to Europe on business for two weeks and needed to borrow $5,000. The loan officer said the bank would need some security for such a loan. The business man then handed over the keys to a Rolls Royce that was parked on the street in front of the bank. Everything checked out and the loan officer accepted the car as collateral for the loan. An employee then drove the Rolls into the bank's underground garage and parked it there. Two weeks later the businessman returned, repaid the $5,000 plus the interest, which came to $15.41. The loan officer said, "We do appreciate your business and this transaction has worked out very nicely, but we are a bit puzzled. While you were away we checked and found that you are a multimillionaire. What puzzles us is why you would bother to borrow $5,000?" The business man replied: "Where else in New York City can I park my car securely for 2 weeks for only 15 bucks?"
Because the text is sent to the output window, it can also be selected and copied elsewhere. This is a very useful tool for debugging embedded SQL. For instance, in the statement just before a recordset is opened, the SQL string is sent via WRAPTRACE() to the output window. The SQL string is then selected and copied into an MS Access97 query where it can be run and debugged. It works great!

Download source - 2 KB

Date Posted: 12/22/98


Comments

  • Good piece of code!

    Posted by Legacy on 09/16/1999 12:00am

    Originally posted by: Dan Hintz

    Steve, this is a nice piece of code!

    Reply
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