Black Box 4/BlackBox.cdr/progc/c_all592.arj/TI870.ASC

Text File | 1992-04-20 | 6KB | 199 lines

  PRODUCT  :  Borland C++                            NUMBER  :  870
  VERSION  :  3.0
       OS  :  DOS
     DATE  :  April 20, 1992                           PAGE  :  1/3

    TITLE  :  Increasing The Number Of Available File Handles




  QUESTION:
       How do I increase the number of FILES available to my
       program under Borland C++ 3.0?


  ANSWER:
       Increasing the number of FILES available to a program in
       Borland C++ involves changing 3 FILES from the RTL (Run-Time
       Library):  _NFILE.H, files.C, and FILES2.C.  The only change
       you actually need to make is in _NFILE.H, where you redefine
       the macro _NFILE_.  The FILES files.C and FILES2.C just need
       to be recompiled to reflect the changes to this macro.
       Assigning a value to this macro will set the maximum number
       of FILES available to your program including the 5 standard
       FILES ( stdin, stdout, stderr, stdaux, stdprn ).

       The changes can be made in two different ways.  One, you can
       simply recompile files.C and FILES2.C in the appropriate
       memory model and link them in with your program.  In the
       IDE, this means adding the two .C FILES to your project.  On
       the command line, this means adding them to your BCC line.

       For example:
            BCC myprog.c FILES.c files2.c

       The effect of this will be that you redefine the symbols in
       the two FILES which have been previously defined in the
       standard libraries, and precedence will go to yours.  You
       can ignore the warnings you will get from the linker if you
       have the Warn Duplicate Symbols option set (/d).

       The other way is to replace the files.C and FILES2.C in the
       standard library with your own.  The advantage of doing this
       is if you always want to have access to more than 20 FILES
       in your programs, you will not always have to add those two
       FILES to your project.  You can replace them by first
       recompiling the FILES using BCC like this:

            BCC -c -mX FILES.c files2.c

       where the X in -mX refers to the memory model of the library
       you want to replace them in ( you will have to do this
       repeatedly if you want to replace all the memory models ).













  PRODUCT  :  Borland C++                            NUMBER  :  870
  VERSION  :  3.0
       OS  :  DOS
     DATE  :  April 20, 1992                           PAGE  :  2/3

    TITLE  :  Increasing The Number Of Available File Handles




       This will result in files.OBJ and FILES2.OBJ which you can
       then add to the appropriate library in the LIB directory
       using TLIB.  For the large model it would look like this:

            TLIB ml.lib +-files.obj +-files2.obj

       Below is the source for the three FILES you need to replace,
       if you do not already have the RTL for Borland C++ 3.0 ( in
       your \BORLANDC\CLIB dir ).  If you choose to add the FILES
       directly to your program, you can merge them into one FILE
       if you choose.  It is not required that the variables be
       defined in separate FILES, this is just how it is done in
       the RTL.

       One final note is that if you want this to be extended to
       Windows programs, you will have to add a call to the Windows
       API funciton SetHandleCount to tell Windows that your
       program needs more FILE HANDLES.


  SOURCE:
       // _NFILE.H
       // Copyright (C) 1992 Borland International, Inc.
       // All Rights Reserved

       // Maximum number of open FILES
       #define _NFILE_ 20
       //..........................................................


       // FILES.C
       // Copyright (C) 1992 Borland International, Inc.
       // All Rights Reserved

       #include <stdio.h>
       #include <_nfile.h>

       #define _F_STDIN    (_F_READ | _F_TERM | _F_LBUF)
       #define _F_STDOUT   (_F_WRIT | _F_TERM | _F_LBUF)
       #define _F_STDERR   (_F_WRIT | _F_TERM)
       #define _F_STDAUX   (_F_RDWR | _F_TERM | _F_BIN)
       #define _F_STDPRN   (_F_WRIT | _F_TERM | _F_BIN)














  PRODUCT  :  Borland C++                            NUMBER  :  870
  VERSION  :  3.0
       OS  :  DOS
     DATE  :  April 20, 1992                           PAGE  :  3/3

    TITLE  :  Increasing The Number Of Available File Handles




       #if !defined( _RTLDLL )

       file _streams [_NFILE_] =
       {
           {0, _F_STDIN,  0, 0, 0, NULL, NULL, 0, (short) stdin},
           {0, _F_STDOUT, 1, 0, 0, NULL, NULL, 0, (short) stdout},
           {0, _F_STDERR, 2, 0, 0, NULL, NULL, 0, (short) stderr},
           {0, _F_STDAUX, 3, 0, 0, NULL, NULL, 0, (short) stdaux},
           {0, _F_STDPRN, 4, 0, 0, NULL, NULL, 0, (short) stdprn}
       };

       #endif  // _RTLDLL
       //..........................................................


       // FILES2.C
       // Copyright (C) 1992 Borland International, Inc.
       // All Rights Reserved

       #include <io.h>
       #include <fcntl.h>
       #include <_nfile.h>

       unsigned _nfile = _NFILE_;

       unsigned int _openfd[_NFILE_] =
       {
            O_RDONLY | O_DEVICE | O_TEXT,
            O_WRONLY | O_DEVICE | O_TEXT,
            O_WRONLY | O_DEVICE | O_TEXT,
            O_RDWR   | O_DEVICE | O_BINARY,
            O_WRONLY | O_DEVICE | O_BINARY
       };
       //..........................................................