NAME
        GetVar -- Returns the value of a local or global variable (V36)

   SYNOPSIS
        len = GetVar( name, buffer, size, flags )
        D0             D1     D2     D3    D4

        long getvar( strptr, strptr, long, ulong )

   FUNCTION
        Gets the value of a local or environment variable.  It is advised to
        only use ASCII strings inside variables, but not required.  This stops
        putting characters into the destination when a n is hit, unless
        GVF_BINARY_VAR is specified.  (The n is not stored in the buffer.)

   INPUTS
        name   - pointer to a variable name.
        buffer - a user allocated area which will be used to store
                 the value associated with the variable.
        size   - length of the buffer region in bytes.
        flags  - combination of type of var to get value of (low 8 bits), and
                 flags to control the behavior of this routine.  Currently
                 defined flags include:

                        GVF_GLOBAL_ONLY - tries to get a global env variable.
                        GVF_LOCAL_ONLY  - tries to get a local variable.
                        GVF_BINARY_VAR  - don't stop at n
                        GVF_DONT_NULL_TERM - no null termination (only valid
                                          for binary variables). (V37)

                 The default is to try to get a local variable first, then
                 to try to get a global environment variable.

   RESULT
        len -   Size of environment variable.  -1 indicates that the
                variable was not defined (if ioerr() returns
                ERROR_OBJECT_NOT_FOUND - it returns ERROR_BAD_NUMBER if
                you specify a size of 0).  If the value would overflow
                the user buffer, the buffer is truncated.  The buffer
                returned is null-terminated (even if GVF_BINARY_VAR is
                used, unless GVF_DONT_NULL_TERM is in effect).  If it
                succeeds, len is the number of characters put in the buffer
                (not including null termination), and ioerr() will return the
                the size of the variable (regardless of buffer size).

   BUGS
        LV_VAR is the only type that can be global.
        Under V36, we documented (and it returned) the size of the variable,
        not the number of characters transferred.  For V37 this was changed
        to the number of characters put in the buffer, and the total size
        of the variable is put in ioerr().
        GVF_DONT_NULL_TERM only works for local variables under V37.  For
        V39, it also works for globals.

   SEE ALSO
        setvar(), deletevar(), findvar(), <dos/var.h>