"Eric" <answer.to.newsgroup@nospam.com> wrote in message
news:i25ll4ljrb8lpnavhdom8a0nbqs7lb9gga@4ax.com...
On Tue, 30 Dec 2008 16:23:35 -0500, "Bill" <Bill_NOSPAM@comcast.net>
wrote:
No one mentioned (I think) that #define is a "pre-processor directive".
The substitution of "4" for "foo" is made before the "real compilation"
even
starts. Hence, no bytes for foo!
Good afternoon, Bill.
Right, I knew that (#define doesn't allocate memory). Just wasn't
sure if most optimizing compilers did the same with const int foo.
I few months ago I was experimenting with the latest MS VC++ compiler
(default settings).
I used a pointer and const_cast to change the value of a const int foo=5,
say to the value 7. The program continued to use the value 5 for foo,
except when I accessed the value of foo via the pointer, then the value was
7. Hence, I deduced, memory was allocated for foo, but the compiler
"optimized away" dynamic references to it. Consider trying it youself and
sharing what happens!