
Since 1998, DevX has helped people start businesses, build websites, and provide enterprise technology to people globally. Interviewing the likes of Microsoft’s co-founder, Steve Ballmer, the publication brings comprehensive, reliable, and accessible insights to the Internet.
Although usually I don’t recommend using macros in C++ code, there are a few exceptions. One such exception is when you want to create a truly immutable constant. Consider the
If you happen to define an object or a function or a constant whose name collides with a macro located elsewhere in a third-party header file, as in: // file
Open source products come with their source code files. Although you can usually install a ready-made executable file, you want to take advantage of the available source code files and
Many modern operating systems support Symmetric Multiprocessing (SMP)?a hardware architecture that uses two or more processors on one machine and enables you to achieve true multitasking. On SMP architectures, multithreaded
The members of an enumerated type are called enumerators. For example: enum Direction { Up, // an enumerator Down // another enumerator }; int main() {} An enumerator’s scope is
I receive many questions from readers asking for guidance on how to port an existing C++ app to a different compiler or platform. Porting software can be very easy or
On modern operating systems, a process consists of an executable file that the OS loads into the system’s memory and executes. A process normally has an entry point and one
Question: How do I drop a table column? Answer: To drop a column, use this syntax: ALTER TABLE Employees DROP COLUMN HomePhone Just remember that you can’t drop a column
Question: How do I create a constructor for a protected member of a class? I have declared the function in the header file but not defined the definition.The error message
Question: I need a query that retrieves info from an Oracle table and a query that retrieves info from a SQL Server table. The info has to be joined together
Question: What are the differences between Provider=MSDASQL.1 and Provider=SQLOLEDB.1 in an “Open” “Select” statement? Also, what is the difference (if any) between “ADO” AND “OLE/DB”? And finally, in Visual Basic,
Question: I have two questions: 1. How can I determine what the server’s lock mode currently is (e.g. WAIT, NO WAIT, etc.), without actually setting it at the same time?
Question: What’s the syntax for outer joins in the where clause in Informix? Answer: The syntax is: SELECT c.customer_num, c.lname, c.company,c.phone, u.call_dtime, u.call_descrFROM customer c, OUTER cust_calls uWHERE c.customer_num =
Question: Using C or C++ for CGI programs, is there a way to make a CGI program that calls another CGI program, and then takes the output of that called
Question: If I have the option of using the uniqueidentifier or int data type for a primary key, will choosing the uniqueidentifier mean a significant performance degradation? Answer: The uniqueidentifier
Const HKEY_LOCAL_MACHINE = &H80000002′ Return True if the system has a math processor” Requires the CheckRegistryKey routineFunction CheckMathProcessor() As Boolean ‘ if a math processor exists, Windows creates ‘ the
Const HKEY_LOCAL_MACHINE = &H80000002′ Return information about the Bios (NT only)” Requires the GetRegistryValue routineSub GetBiosInfo(BiosDate As String, BiosVersion As String) ‘ These keys appear to exist only on NT
Private Declare Function GetVersion Lib “kernel32″ () As LongConst HKEY_LOCAL_MACHINE = &H80000002′ Modify the name of the registered user and organization” Requires the SetRegistryValue functionSub SetRegisteredUser(ByVal UserName As String, Optional
Const HKEY_LOCAL_MACHINE = &H80000002′ Information about the CPU’ you can pass a number 1 to the last argument to retrieve’ information on all the processors in a multi-CPU system” Returns
Const HKEY_LOCAL_MACHINE = &H80000002′ modify the value of a setting for the VB IDE from the Registry’ Important: only works with VB6” New values are effective when VB is restarted”
Const HKEY_LOCAL_MACHINE = &H80000002′ Get the path of a Windows application’ or an empty string if the application isn’t registered” this routine only works for those applications that register’ themselves
Const HKEY_LOCAL_MACHINE = &H80000002′ read the name and path of the external HTML editor’ configured for the VB environment” Requires the GetRegistryValue functionFunction GetExternalHTMLEditor() As String ‘ Note that the
Const HKEY_LOCAL_MACHINE = &H80000002′ get the list of ODBC drivers through the registry” returns a collection of strings, each one holding the’ name of a driver, e.g. “Microsoft Access Driver
Const HKEY_LOCAL_MACHINE = &H80000002′ modify the name and path of the external HTML editor’ configured in the Tools|Options|Advanced tab” Changes apply immediately (no need to restart VB)” Requires the SetRegistryValue
Const HKEY_LOCAL_MACHINE = &H80000002′ Return information about an ODBC driver” The 1st argument must be an ODBC driver name,’ as returned by the GetODBCDrivers function’ Not all drivers return the
Const HKEY_LOCAL_MACHINE = &H80000002′ Return the number of processors” Requires the CheckRegistryKey routineFunction GetNumberOfCPUs() As Integer Dim keyName As String ‘ loop on the subkeys of HKEY_LOCAL_MACHINEHardwareDescriptionSystem ‘ CentralProcessor ‘
Const HKEY_LOCAL_MACHINE = &H80000002′ read the value of a setting for the VB IDE from the Registry’ Important: only works with VB6” Possible values for SettingName are’ AlignToGrid (returns 0/1)’
While the DIV element can be used to designate block-level elements such as paragraphs and list items, SPAN is used within a block. And while most browsers will insert a
Using the frame’s location object, you can load a number of different files into a frame at runtime. As you do when building any project using frames, first build a
Avoid putting double quotes inside of double quotes in your HTML code. You may not get a compiler error, but your script just won’t work. Instead, substitute single quotes for











