QUALIFYING VARIABLE NAMES

 

  PRODUCT  :  TURBO C                                NUMBER  :  455

  VERSION  :  2.0

       OS  :  PC-DOS

     DATE  :  OCTOBER 31, 1988                         PAGE  :  1/3

    TITLE  :  QUALIFYING VARIABLE NAMES

  The  subsection "Qualifying Variable Names" on  page  57  of  the

  Turbo  C  User's   Guide   is  inaccurate.    Use  the  following

  information as documentation:

  There  are  three  typical situations in which it is desirable to

  fully qualify a variable name used in an expression.

      o  To qualify a static  variable  in  another module, use the

         following syntax:

              .<module name>.<variable name>

      o  To qualify a local variable  in a global function, use the

         following syntax:

              <function name>.<variable name>

      o  To qualify a local variable  in a static function, use the

         following syntax:

              .<module name>.<function name>.<variable name>

  The function name is  only  used when looking at a variable local

  to the function.  For  example, suppose your program contains two

  modules (FIRSTMOD, MYSUBS):

  /* FIRSTMOD.C */

  int a = 1;

  main()

  {

       int b = 2;

       myfunc();

       printf("%d", i);

  }

  /* MYSUBS.C */

  static int e = 3;

  static void localfunc(void)

  {

       int d = 4;

  PRODUCT  :  TURBO C                                NUMBER  :  455

  VERSION  :  2.0

       OS  :  PC-DOS

     DATE  :  OCTOBER 31, 1988                         PAGE  :  2/3

    TITLE  :  QUALIFYING VARIABLE NAMES

       printf("End of the road\n");

  }

  void myfunc(void)

  {

       int c = 5;

       localfunc();

  }

  To watch the global variable a, use:

            a

  To watch the local variable b in main, use:

            main.b

  To watch the local variable c in myfunc, use:

            myfunc.c

  To watch the local variable d in the  static  function localfunc,

  use:

            .mysubs.localfunc.d

  To watch the static variable e in module2, use:

            .mysubs.e

  The  necessity  of  qualifiers  will   depend   on   the  current

  instruction pointer.  For instance, if your program is running in

  main, it is  unnecessary  to  qualify  the  variable  b  with the

  function name main.  Likewise,  if your program is running inside

  the  MYSUBS  module,  it is unnecessary to qualify the variable e

  with the module name.

  Additionally, it is not  possible  to watch an auto (local) in an

  inactive scope.  Since the function myfunc calls localfunc, it is

  possible to watch the local variables of myfunc from localfunc --

  the variables in myfunc are not removed when localfunc is called.

  However, once myfunc returns to main, it is no longer possible to

  PRODUCT  :  TURBO C                                NUMBER  :  455

  VERSION  :  2.0

       OS  :  PC-DOS

     DATE  :  OCTOBER 31, 1988                         PAGE  :  3/3

    TITLE  :  QUALIFYING VARIABLE NAMES

  view its local variables  --  local  variables are discarded when

  the function in which  they  are  located  returns to the calling

  function.

  DISCLAIMER: You  have the right to use this technical information

  subject to the terms  of  the  No-Nonsense License Statement that

  you received with  the  Borland product to which this information

  pertains.