Macro nes::rw_read

macro_rules! rw_read {
    ( $rw:expr ) => { ... };
    ( $rw:expr, $error:ident ) => { ... };
    ( $rw:expr, $error:path ) => { ... };
    ( $rw:expr, $rw:path, $( $arg:expr ),* ) => { ... };
}

This macro helps to lock rw_lock(calls read) and returns error if it is poisoned(second thread has locked the RwLock and panicked).

Where are 4 forms:

let guard=rw_read(rw_lock) returns "Error::Poisoned"

let guard=rw_read(rw_lock,ErrorName) returns "ErrorName::Poisoned"

let guard=rw_read(rw_lock,ErrorName::Variant) returns "ErrorName::Variant"

let guard=rw_read(rw_lock,ErrorName::Variant,arg1,arg2,...) returns "ErrorName::Variant(arg1,arg2,...)"