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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documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
CHAIN Statement Details
  Summary  Details  Example                Contents  Index  Back
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 CHAIN filespec$
 
 Usage Notes
   ■ Programs running in the programming environment assume a .BAS extension
     if no extension is given and cannot chain to executable files (files
     with a .COM or .EXE extension).
 
   ■ Programs running outside the programming environment assume an .EXE
     extension and cannot chain to Basic (.BAS) source files.
 
   ■ You can pass variables between programs using the COMMON Statement to
     set up a blank COMMON block. See: COMMON Statement
 
   ■ When you compile a program outside the Visual Basic environment, the
     VBDRT10.LIB library does not support COMMON. To use COMMON with chained
     programs outside the environment, you must either:
     • Select the EXE Requiring Run-Time Module option from the Make EXE File
       dialog when you compile. This is the default option (uses the file
       VBDRT10.EXE).
     • Compile from the command line (BC.EXE) without the /O option.
 
   ■ When programs use VBDRT10.EXE, files are left open during chaining
     unless they are explicitly closed with the CLOSE statement.
     See: CLOSE Statement
 
   ■ CHAIN is similar to RUN; the main differences are that RUN closes all
     open files and does not support data blocks declared with COMMON.
     See: RUN Statement
 
   ■ CHAIN is equivalent to RUN when the /O compiler option is used.
 
   ■ If you compile a program (without /O) that does not use ISAM and then
     attempt to CHAIN to another non-/O program that does use ISAM, Visual
     Basic generates the error message, "Error loading run-time module
     (VBDRT10.EXE) - ISAM support removed." Likewise, if you compile a
     program (without /O) that does not use forms and then attempt to CHAIN
     to another non-/O program that does use forms, Visual Basic generates
     the error message, "Error loading run-time module (VBDRT10.EXE) - form
     support removed."