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7532 :: windows - msys2 - rdynamic

• mantielero (orginal) [2021-02-19T00:37:36+01:00] view original

  I have been investigating this issue. After some struggle I have managed to reproduce it.

  I am using MSYS2, so that I could install the package dlfcn:

  
  $ pacman -S mingw-w64-x86_64-dlfcn
  Run

  Now I am getting the same error:

  
  λ nim c --threads:on --tlsEmulation:off ex00
  Hint: used config file 'C:\Users\jose\Documents\nim-1.4.2\config\nim.cfg' [Conf]
  Hint: used config file 'C:\Users\jose\Documents\nim-1.4.2\config\config.nims' [Conf]
  ................
  c:\Users\jose\Downloads\VapourSynth.nim\VapourSynth.nim-master\src\wrapper\vsframe.nim(403, 7) Hint: 'ssW' is declared but not used [XDeclaredButNotUsed]
  c:\Users\jose\Downloads\VapourSynth.nim\VapourSynth.nim-master\src\wrapper\vsframe.nim(404, 7) Hint: 'ssH' is declared but not used [XDeclaredButNotUsed]
  c:\Users\jose\Downloads\VapourSynth.nim\VapourSynth.nim-master\src\wrapper\vsframe.nim(405, 7) Hint: 'bytesPerSample' is declared but not used [XDeclaredButNotUsed]
  ..
  c:\Users\jose\Downloads\VapourSynth.nim\VapourSynth.nim-master\src\vsmacros\filter.nim(241, 7) Hint: 'srcNumPlanes' is declared but not used [XDeclaredButNotUsed]
  c:\Users\jose\Downloads\VapourSynth.nim\VapourSynth.nim-master\src\wrapper\helper.nim(6, 7) Hint: 'nodes' is declared but not used [XDeclaredButNotUsed]
  c:\Users\jose\Downloads\VapourSynth.nim\VapourSynth.nim-master\src\wrapper\vsmap.nim(282, 3) Hint: 'VSType' is declared but not used [XDeclaredButNotUsed]
  Hint:  [Link]
  gcc.exe: error: unrecognized command-line option '-rdynamic'
  Error: execution of an external program failed: 'gcc.exe   -o c:\Users\jose\Downloads\VapourSynth.nim\VapourSynth.nim-master\test\ex00.exe  C:\Users\jose\nimcache\ex00_d\stdlib_assertions.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_locks.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_sharedlist.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_widestrs.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_io.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_system.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_parseutils.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_unicode.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_strutils.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_strformat.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_options.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_streams.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_tables.nim.c.o C:\Users\jose\nimcache\ex00_d\@m..@[email protected] C:\Users\jose\nimcache\ex00_d\@mex00.nim.c.o  -rdynamic -Wl,-wrap,dlopen   '
  Run

  with:

  
  λ gcc -v
  ...
  gcc version 10.2.0 (Rev6, Built by MSYS2 project)
  Run

  The first question is:

  • Why do I have -rdynamic? From what I have read it looks it has nothing to do with windows.

  
  -rdynamic
      Pass the flag -export-dynamic to the ELF linker, on targets that support it. This
      instructs the linker to add all symbols, not only used ones, to the dynamic symbol
      table. This option is needed for some uses of dlopen or to allow obtaining backtraces
      from within a program.
  Run

  Secondly, I have tried:

  • removing -rdynamic

  
  λ gcc.exe  -o c:\Users\jose\Downloads\VapourSynth.nim\VapourSynth.nim-master\test\ex00.exe  C:\Users\jose\nimcache\ex00_d\stdlib_assertions.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_locks.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_sharedlist.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_widestrs.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_io.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_system.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_parseutils.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_unicode.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_strutils.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_strformat.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_options.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_streams.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_tables.nim.c.o C:\Users\jose\nimcache\ex00_d\@m..@[email protected] C:\Users\jose\nimcache\ex00_d\@mex00.nim.c.o  -Wl,-wrap,dlopen
  C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\jose\nimcache\ex00_d\@m..@[email protected]:@m..@[email protected]:(.text+0x19): undefined reference to `dlopen'
  collect2.exe: error: ld returned 1 exit status
  Run

  • Removing dlopen:

  
  λ gcc.exe  -o c:\Users\jose\Downloads\VapourSynth.nim\VapourSynth.nim-master\test\ex00.exe  C:\Users\jose\nimcache\ex00_d\stdlib_assertions.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_locks.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_sharedlist.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_widestrs.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_io.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_system.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_parseutils.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_unicode.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_strutils.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_strformat.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_options.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_streams.nim.c.o C:\Users\jose\nimcache\ex00_d\stdlib_tables.nim.c.o C:\Users\jose\nimcache\ex00_d\@m..@[email protected] C:\Users\jose\nimcache\ex00_d\@mex00.nim.c.o  -Wl,-wrap
  C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\jose\nimcache\ex00_d\@m..@[email protected]:@m..@[email protected]:(.text+0x19): undefined reference to `__real_dlopen'
  collect2.exe: error: ld returned 1 exit status
  Run

  Any idea how should I compile this? Any particular option for windows?

---

• guibar (orginal) [2021-02-19T11:50:48+01:00] view original

  Hello,

  In src/wrapper/VSScript_Wrapper.nim there is this horrible POSIX-specific code:

  {. passL:"-rdynamic -Wl,-wrap,dlopen".}
  
  {.emit: """
  #include <dlfcn.h>
  #include <stdio.h>
  
  void *__real_dlopen(const char *filename, int flags);
  
  void *__wrap_dlopen(const char *filename, int flags)
  {
    //printf("shadow dlopen with RTLD_GLOBAL: %s\n", filename);
    //fflush(stdout);
    return __real_dlopen(filename, RTLD_NOW | RTLD_GLOBAL);
  }
  """.}
  Run

  It seems to serve no purpose at all even on not-windows (Nim already use dlopen/LoadLibrary for loading dlls after all).

  I tried to cut it out with a

  when not defined(windows):
    Horrible code
  Run

  and it compiles on my windows machine. (It fails at execution with ' plugin "com.vapoursynth.ffms2" not installed properly in your computer' but I did not try hard to install VapourSynth).

  BTW if loading dlls explicitly in Nim code is needed it is probably better to use stdlib's dynlib module instead of using a msys2 package.

---

• mantielero (orginal) [2021-02-19T15:41:36+01:00] view original

  Thanks a lot. That solves the issue. I will update the code.

---