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author | Adam Carpenter <gitlab@53hor.net> | 2019-07-09 15:14:04 -0400 |
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committer | Adam Carpenter <gitlab@53hor.net> | 2019-07-09 15:14:04 -0400 |
commit | 7e8ee5ed9cad6484e9f13f81731b102ced58402e (patch) | |
tree | 5395402ab07bbb5a659dbd68c701e22a1227202f /meap/meap-code/ch6/ch6-memscan-1/src/main.rs | |
download | learning-rust-7e8ee5ed9cad6484e9f13f81731b102ced58402e.tar.xz learning-rust-7e8ee5ed9cad6484e9f13f81731b102ced58402e.zip |
Init.
Diffstat (limited to 'meap/meap-code/ch6/ch6-memscan-1/src/main.rs')
-rwxr-xr-x | meap/meap-code/ch6/ch6-memscan-1/src/main.rs | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/meap/meap-code/ch6/ch6-memscan-1/src/main.rs b/meap/meap-code/ch6/ch6-memscan-1/src/main.rs new file mode 100755 index 0000000..b92da20 --- /dev/null +++ b/meap/meap-code/ch6/ch6-memscan-1/src/main.rs @@ -0,0 +1,14 @@ +fn main() { + let mut n_nonzero = 0; + + for i in 0..10000 { + let ptr = i as *const u8; // <1> Convert `i` to a `pass:[*const T]`, a "`raw pointer`" of type `u8`. Raw pointers allow programmers to inspect raw memory addresses. We treat every address as a unit, ignoring the fact that most values span multiple bytes. + let byte_at_addr = unsafe { *ptr }; // <2> _Dereference_ the pointer. That is, read the value at address `i`. Another way of saying this is read the value being pointed to. + + if byte_at_addr != 0 { + n_nonzero += 1; + } + } + + println!("non-zero bytes in memory: {}", n_nonzero); +}
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