#9215: GHC 7.8.2 mingw-w64: symbol not found in link -------------------------------------+------------------------------------- Reporter: stuartallenmills | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Windows | Architecture: x86_64 | (amd64) Type of failure: Other | Test Case: Blocked By: 9218 | Blocking: Related Tickets: #9218 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Phyx-): I have just removed all the special cases from the linker in Phab:D1805 which means GHCi will *probably* not load this library anymore either... If it ever did.. I also think that their patch only fixes 64bit compilation but not 32bit. The prefixed _ has nothing to do with the usual name mangling of functions. Instead it was a conscious choice by Microsoft to deprecate the functions that are not part of the C standard (`strdup` is `POSIX`, not `C`, and the Microsoft POSIX Subsystem was never fully POSIX compliant afaik, SUA was but that's now deprecated.) into a different namespace following the C++ ISO naming convention. https://msdn.microsoft.com/en- us/subscriptions/7e259932-c6c8-4c1a-9637-639e591681a5(v=vs.90) in order to free up the namespace to user defined functions. As in, on Windows `strdup` should always be used as `_strdup` regardless if it's 32 or 64bit. And indeed, if you look at the export table of the standard C runtime on Windows (msvcrt) which both GHCi and MingW-w64 link to: {{{
dumpbin /exports c:\Windows\SysWOW64\msvcrt.dll | findstr "strdup" 859 35A 000247AD _strdup 860 35B 000801D6 _strdup_dbg
dumpbin /exports c:\Windows\System32\msvcrt.dll | findstr "strdup" 742 2E5 000152D0 _strdup 743 2E6 0006635C _strdup_dbg }}}
Both the 32bit and the 64bit version report only the undeprecated function, always with the _ prefix. So this is not a GHC bug, nor a Windows one. The library just did not use the correct function as stated on MSDN. The correct fix would probably be {{{ #if _WIN32 #define STRDUP _strdup #else #define STRDUP strdup #endif }}} Because it will always be the case on Windows. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9215#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler