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The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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─────Dynamic-Link Libraries─────────────────────────────────────────────────
 
     What Is a Dynamic-Link Library?
 
     A DLL contains executable code for common functions, as does a
     standard library. However, in DLLs code for functions is not
     copied into the executable file. Instead, the library itself is
     loaded into memory at run time, along with the executable file.
 
     Advantages of Dynamic Linking
 
     DLLs serve much the same purpose that standard libraries do, but
     they also have the following advantages:
 
       1. Applications require less disk space.
 
          With dynamic linking, several different applications can use
          the same dynamic-link function stored in one place. Without
          dynamic linking, the code for the function must be repeated
          in every program.
 
       2. Code and data segments can be shared.
 
          Code and data segments loaded from a DLL can be shared.
          Without dynamic linking, such sharing is not possible because
          each file has its own copy of all the code and data it uses.
          By using dynamic linking to share segments, you can use
          memory more efficiently.
 
       3. Libraries and applications are independent.
 
          DLLs can be updated any number of times without relinking the
          applications that use them. If you use third-party libraries,
          this is particularly convenient. You receive the updated DLL
          from the third-party developers and copy the new library onto
          your disk. At run time, your applications automatically call
          the updated functions.
 
       4. Applications link faster.
 
          With dynamic linking, the executable code for a dynamic-link
          function is not copied into the application's executable
          file. Instead, only an import definition is copied.
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