Defines a block of code that catches the first exception type thrown in the preceding TRY block.
CATCH(exception_class, exception_object_pointer_name )
The exception-processing code can interrogate the exception object, if appropriate, to get more information about the specific cause of the exception. Invoke the THROW_LAST macro to shift processing to the next outer exception frame. End the TRY block with an END_CATCH macro.
If exception_class is the class CException, then all exception types will be caught. You can use the CObject::IsKindOf member function to determine which specific exception was thrown. A better way to catch several kinds of exceptions is to use sequential AND_CATCH statements, each with a different exception type.
The exception object pointer is created by the macro. You do not need to declare it yourself.
Note
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The CATCH block is defined as a C++ scope delineated by braces. If you declare variables in this scope, they are accessible only within that scope. This also applies to exception_object_pointer_name. |
For more information on exceptions and the CATCH macro, see the article Exceptions.
CFile* pFile = NULL; // Constructing a CFile object with this override may throw // a CFile exception and won't throw any other exceptions. // Calling CString::Format() may throw a CMemoryException, // so we have a catch block for such exceptions, too. Any // other exception types this function throws will be // routed to the calling function. TRY { pFile = new CFile(_T( "C:\\WINDOWS\\SYSTEM.INI"), CFile::modeRead | CFile::shareDenyNone); ULONGLONG dwLength = pFile->GetLength(); CString str; str.Format(_T("Your SYSTEM.INI file is %I64u bytes long.") , dwLength); AfxMessageBox(str); } CATCH(CFileException, pEx) { // Simply show an error message to the user. pEx->ReportError(); } AND_CATCH(CMemoryException, pEx) { // We can't recover from this memory exception, so we'll // just terminate the app without any cleanup. Normally, // an application should do everything it possibly can to // clean up properly and not call AfxAbort(). AfxAbort(); } END_CATCH // If an exception occurs in the CFile constructor, // the language will free the memory allocated by new // and will not complete the assignment to pFile. // Thus, our cleanup code needs to test for NULL. if (pFile != NULL) { pFile->Close(); delete pFile; }
Header: afx.h