Package: gcc-3.3 [This is also present in gcc-3.2, and probably all 3.x versions; it is inapplicable for 2.95, which didn't support dynamic arrays]
int main(void)
{
int foo = 0;
int bar;
int len = 5;
switch(foo)
{
case 0:
bar = 1;
char buf[len];
}
}
[EMAIL PROTECTED]:~$ gcc-3.2 -g -o foo foo.c
foo.c: In function `main':
foo.c:6: warning: unreachable code at beginning of switch statement
Note that this only occurs at -g2 or higher; I'm not sure why offhand.
The line number is at best misleading; the complaint is about the
scope of the dynamic array buf.
I haven't investigated it, because I'm mildly familiar with the code
in gcc that's responsible (most of gcc/stmt.c), and it's utterly
disgusting. However, I recognise the symptoms; it is likely that the
code to set up the dynamic array has been inserted at the top of the
binding contour - between the { and the case - which is invalid, as
that space is always jumped over. This is supported by observing that
if you manually insert a new contour, the warning disappears:
int main(void)
{
int foo = 0;
int bar;
int len = 5;
switch(foo)
{
case 0:
{
bar = 1;
char buf[len];
}
}
}
I'm not sure whether the original code is supposed to compile or not;
I suspect that it currently miscompiles. What the heck is the scope of
a variable declared in this position?
--
.''`. ** Debian GNU/Linux ** | Andrew Suffield
: :' : http://www.debian.org/ |
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