tiemann@LURCH.STANFORD.EDU (Michael Tiemann) (11/20/89)
Date: Sun, 19 Nov 89 15:36:34 PST
From: raulmill%aludra.usc.edu@usc.edu (Raul Deluth Rockwell)
Code:
a->Rest_Length = t /* refigure length count */
&& 1 + a->Rest->Rest_Length;
Code purpose: If t is a null pointer, count is zero, otherwise count
indicates list length.
Problem: works fine for generating a->Rest_Length = 0 or
a->Rest_Length = 1, won't make a->Rest_Length = 2.
Types:
struct arg_list_struct {
unsigned Line;
char * Source;
union {
signed short Integer;
unsigned Coord;
struct arg_list_struct * List;
char * String;
struct sym_struct * Sym;
} Arg;
arg_type_t Arg_Type; /* an enum */
struct arg_list_struct * Rest;
unsigned Rest_Length;
} *a, *t;
compiler version: gcc version 1.36
compiler options: -g -sun4
environment: Sun-4/260 with 32 MB of memory, running SunOS Release 4.0.3-GFX
steps taken to verify presence of compiler problem rather than user
problem: ran offending computation through gdb (gdb gave 2 where
compiled code gave 1).
Raul Rockwell
INTERNET: raulmill@usc.edu !
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This is pilot error: the result of an && expression always evaluates
to 0 or 1. Since GCC is right and GDB is wrong, it is a GDB bug.
To Raul, this is what you want:
Code:
/* refigure length count */
a->Rest_Length = (t ? 1 + a->Rest->Rest_Length : 0);
Code purpose: If t is a null pointer, count is zero, otherwise count
indicates list length.
Michael