pub fn assert_no_alloc<T, F: FnOnce() -> T>(func: F) -> TExpand description
Calls the func closure, but forbids any (de)allocations.
If a call to the allocator is made, the program will abort with an error,
print a warning (depending on the warn_debug feature flag. Or ignore
the situation, when compiled in --release mode with the disable_release
feature flag set (which is the default)).
Examples found in repository?
examples/main.rs (lines 14-23)
7fn main() {
8 println!("Alloc is allowed. Let's allocate some memory...");
9 let mut vec_can_push = Vec::new();
10 vec_can_push.push(42);
11
12 println!();
13
14 let fib5 = assert_no_alloc(|| {
15 println!("Alloc is forbidden. Let's calculate something without memory allocations...");
16
17 fn fib(n: u32) -> u32 {
18 if n<=1 { 1 }
19 else { fib(n-1) + fib(n-2) }
20 }
21
22 fib(5)
23 });
24 println!("\tSuccess, the 5th fibonacci number is {}", fib5);
25 println!();
26
27 assert_no_alloc(|| {
28 println!("Alloc is forbidden. Let's allocate some memory...");
29 let mut vec_cannot_push = Vec::new();
30 vec_cannot_push.push(42); // panics
31 });
32
33 println!("This will not be executed if the above allocation has aborted.");
34}