Attribute Macro static_init::destructor

#[destructor]

Attribute for functions run at program termination (after main)

#[destructor]
unsafe fn droper () {
// run before main start
}

The execution order of destructors is unspecified. Nevertheless on ELF plateform (linux,any unixes but mac) and windows plateform a priority can be specified using the syntax destructor(<num>) where <num> is a number included in the range [0 ; 2¹⁶-1].

Destructors without priority are run first (in unspecified order), then destructors with priority 0 are run, then destructors with priority number 1,... finaly destructors with priority 65535 are run.

Safety

Destructor functions must be unsafe. Any access to statics dropped with an equal or lower priority will cause undefined behavior.

#[destructor(1)]
unsafe fn first () {
// run after main return
}

#[destructor(0)]
unsafe fn then () {
// run after main return
}