#11829: C++ does not catch exceptions when used with Haskell-main and linked by ghc -------------------------------------+------------------------------------- Reporter: pl | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.10.3 Resolution: | Keywords: c++ | exceptions Operating System: MacOS X | Architecture: | Unknown/Multiple Type of failure: Runtime crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by syntheorem): I just ran into this, but the `-lto_library` flag didn't fix the problem (Clang is passing it automatically now anyway). What ultimately worked for me was adding `-Wl,-keep_dwarf_unwind` to my `ld-options`. I tried your method of writing `main` in C++ and manually linking via Clang to see what it does. Interestingly, just linking against the Haskell libraries and RTS with no other flags broke exceptions for me. But I also got the same warning: {{{ ld: warning: could not create compact unwind for _ffi_call_unix64: does not use RBP or RSP based frame }}} I searched for that and discovered that you could use `-Wl,-no_compact_unwind` to disable the warning; and GHC already passes that flag to Clang during linking. But that option also somehow breaks the exception handling tables; the system will fall back on the DWARF exception tables if you include them by passing `-Wl,-keep_dwarf_unwind`. Also worth noting that I'm on macOS 10.12.6, which is about a year out of date, so the issue might be fixed on the most recent version. Using GHC 8.4.3 and Clang 6.0.1. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11829#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler