Function libloading::os::unix::with_dlerror
source · pub fn with_dlerror<T, F, Error>(
closure: F,
error: fn(_: &CStr) -> Error
) -> Result<T, Option<Error>>
Expand description
Run code and handle errors reported by dlerror
.
This function first executes the closure
function containing calls to the functions that
report their errors via dlerror
. This closure may return either None
or Some(*)
to
further affect operation of this function.
In case the closure
returns None
, with_dlerror
inspects the dlerror
. dlerror
may
decide to not provide any error description, in which case Err(None)
is returned to the
caller. Otherwise the error
callback is invoked to allow inspection and conversion of the
error message. The conversion result is returned as Err(Some(Error))
.
If the operations that report their errors via dlerror
were all successful, closure
should
return Some(T)
instead. In this case dlerror
is not inspected at all.
§Notes
The whole dlerror
handling scheme is done via setting and querying some global state. For
that reason it is not safe to use dynamic library loading in MT-capable environment at all.
Only in POSIX 2008+TC1 a thread-local state was allowed for dlerror
, making the dl* family of
functions possibly MT-safe, depending on the implementation of dlerror
.
In practice (as of 2020-04-01) most of the widely used targets use a thread-local for error state and have been doing so for a long time.