MinGw64 compiler bugged in 2018a ?

I try to build a mex of a file who used lib c:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\x86_64-w64-mingw32\lib\libiphlpapi.a

When i use the mex command it looks for .lib files. But all the libraries are .a in the folder which i specified with -L . How to make linker to look for .a files ?

Here is the command:

mex -v -L"c:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\x86_64-w64-mingw32\lib"  -llibiphlpapi.a  MACAddress_mex.c
Verbose mode is on.
... Looking for compiler 'MinGW64 Compiler (C)' ...
... Looking for environment variable 'MW_MINGW64_LOC' ...Yes ('C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset').
... Looking for file 'C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc.exe' ...Yes.
... Looking for folder 'C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset' ...Yes.
Found installed compiler 'MinGW64 Compiler (C)'.
Set PATH = C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin;C:\MATLAB\R2018a\extern\include\win64;C:\MATLAB\R2018a\extern\include;C:\MATLAB\R2018a\simulink\include;C:\MATLAB\R2018a\lib\win64;C:\ProgramData\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Program Files\TortoiseSVN\bin;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Program Files\dotnet\;C:\TDM-GCC-64\bin;C:\MATLAB\R2018a\bin;C:\Users\timo\AppData\Local\Microsoft\WindowsApps;c:\SysGCC\mingw64\bin;
Set INCLUDE = C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\include;;C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\include;;
Set LIB = C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\lib;;C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\lib;;
Set MW_TARGET_ARCH = win64;win64;
Set LIBPATH = C:\MATLAB\R2018a\extern\lib\win64;C:\MATLAB\R2018a\extern\lib\win64;
Error using mex
MEX cannot find library 'libiphlpapi.a' specified with the -l option.
 MEX looks for a file with one of the names:
 liblibiphlpapi.a.lib
 libiphlpapi.a.lib
 Please specify the path to this library with the -L option.

Ps: it worked if i renamed the libiphlpapi.a to libiphlpapi.lib , but seems like a hack and not a proper solution . I think MSVC and MinGW operate differently w.r.t. expected extensions. While MSVC normally creates static libraries with a .lib extension, MinGW/MSYS respects the Unix defaults and requires a .a

[timo]

I also tried

mex -v -L"c:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\x86_64-w64-mingw32\lib"  -liphlpapi.a  MACAddress_mex.c

And also tried

mex -v -L"c:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\x86_64-w64-mingw32\lib"  -liphlpapi  MACAddress_mex.c

[Walter Roberson]

Try

mex -v -L"c:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\x86_64-w64-mingw32\lib"    MACAddress_mex.c iphlpapi.a

[timo]

OK the strange thing it solved itself after i did the next

1. switched he compiler to Visual Studio 2017 2. made the mex only with the mex -v -liphlpapi MACAddress_mex.c 3. restarted pc , ran mex-setup and selected MinGW for C

Now it works with MinGW . I even tested that it uses iphlpapi.a by deleting it from the compiler folder and seeing indeed that it cannot find the lib

Now the MinGW log looks also different than what it looked yesterday. WTF is going on lol ?

>> mex -v  -liphlpapi  MACAddress_mex.c
Verbose mode is on.
... Looking for compiler 'MinGW64 Compiler (C)' ...
... Looking for environment variable 'MW_MINGW64_LOC' ...Yes ('C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset').
... Looking for file 'C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc.exe' ...Yes.
... Looking for folder 'C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset' ...Yes.
Found installed compiler 'MinGW64 Compiler (C)'.
Set PATH = C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin;C:\MATLAB\R2018a\extern\include\win64;C:\MATLAB\R2018a\extern\include;C:\MATLAB\R2018a\simulink\include;C:\MATLAB\R2018a\lib\win64;C:\ProgramData\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Program Files\TortoiseSVN\bin;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Program Files\dotnet\;C:\TDM-GCC-64\bin;C:\MATLAB\R2018a\bin;C:\Users\timo\AppData\Local\Microsoft\WindowsApps;c:\SysGCC\mingw64\bin;
Set INCLUDE = C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\include;;C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.13.26128\include;C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.13.26128\atlmfc\include;C:\Program Files (x86)\Windows Kits\10\\include\10.0.16299.0\ucrt;C:\Program Files (x86)\Windows Kits\10\\include\10.0.16299.0\shared;C:\Program Files (x86)\Windows Kits\10\\include\10.0.16299.0\um;C:\Program Files (x86)\Windows Kits\10\\include\10.0.16299.0\winrt;C:\MATLAB\R2018a\extern\include;
Set LIB = C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\lib;;C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.13.26128\lib\x64;C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.13.26128\atlmfc\lib\x64;C:\Program Files (x86)\Windows Kits\10\\Lib\10.0.16299.0\ucrt\x64;C:\Program Files (x86)\Windows Kits\10\\lib\10.0.16299.0\um\x64;C:\MATLAB\R2018a\lib\win64;
Set MW_TARGET_ARCH = win64;win64;
Set LIBPATH = C:\MATLAB\R2018a\extern\lib\win64;C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.13.26128\lib\x64;C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.13.26128\atlmfc\lib\x64;
Options file details
-------------------------------------------------------------------
  Compiler location: C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset
  Options file: C:\Users\timo\AppData\Roaming\MathWorks\MATLAB\R2018a\mex_C_win64.xml
  CMDLINE2 : C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc -m64 -Wl,--no-undefined -shared -static -s -Wl,"C:\MATLAB\R2018a/extern/lib/win64/mingw64/exportsmexfileversion.def" C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\MACAddress_mex.obj C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\c_mexapi_version.obj   -liphlpapi  -L"C:\MATLAB\R2018a\extern\lib\win64\mingw64" -llibmx -llibmex -llibmat -lm -llibmwlapack -llibmwblas -o MACAddress_mex.mexw64
  CC : C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc
  COMPILER : C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc
  DEFINES : -DMATLAB_DEFAULT_RELEASE=R2017b  -DUSE_MEX_CMD   -m64 -DMATLAB_MEX_FILE 
  MATLABMEX : -DMATLAB_MEX_FILE 
  CFLAGS : -fexceptions -fno-omit-frame-pointer
  INCLUDE : -I"C:\MATLAB\R2018a/extern/include" -I"C:\MATLAB\R2018a/simulink/include" -I"C:\MATLAB\R2018a/extern\lib\win64\mingw64"
  COPTIMFLAGS : -O -DNDEBUG
  CDEBUGFLAGS : -g
  LD : C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc
  LINKER : C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc
  LDTYPE : -shared -static
  LDFLAGS : -m64 -Wl,--no-undefined
  LINKEXPORT : -Wl,"C:\MATLAB\R2018a/extern/lib/win64/mingw64/mexFunction.def"
  LINKEXPORTVER : -Wl,"C:\MATLAB\R2018a/extern/lib/win64/mingw64/exportsmexfileversion.def"
  LIBLOC : C:\MATLAB\R2018a\extern\lib\win64\mingw64
  LINKLIBS : -liphlpapi  -L"C:\MATLAB\R2018a\extern\lib\win64\mingw64" -llibmx -llibmex -llibmat -lm -llibmwlapack -llibmwblas
  LDOPTIMFLAGS : -s
  LDDEBUGFLAGS : -g
  OBJEXT : .obj
  LDEXT : .mexw64
  SETENV : set COMPILER=C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc
                set CXXCOMPILER=C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\g++
                set COMPFLAGS=-c -fexceptions -fno-omit-frame-pointer -DMATLAB_DEFAULT_RELEASE=R2017b  -DUSE_MEX_CMD   -m64 -DMATLAB_MEX_FILE  -DMATLAB_MEX_FILE 
                set CXXCOMPFLAGS=-c -fexceptions -fno-omit-frame-pointer -std=c++11 -DMATLAB_DEFAULT_RELEASE=R2017b  -DUSE_MEX_CMD   -m64 -DMATLAB_MEX_FILE  -DMATLAB_MEX_FILE 
                set OPTIMFLAGS=-O -DNDEBUG
                set DEBUGFLAGS=-g
                set LINKER=C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc
                set CXXLINKER=C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\g++
                set LINKFLAGS=-m64 -Wl,--no-undefined -shared -static -liphlpapi -llibiphlpapi   -L"C:\MATLAB\R2018a\extern\lib\win64\mingw64" -llibmx -llibmex -llibmat -lm -llibmwlapack -llibmwblas -Wl,"C:\MATLAB\R2018a/extern/lib/win64/mingw64/mexFunction.def"
                set LINKDEBUGFLAGS=-g
                set NAME_OUTPUT=-o "%OUTDIR%%MEX_NAME%%MEX_EXT%"
  MINGWROOT : C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset
  MATLABROOT : C:\MATLAB\R2018a
  ARCH : win64
  SRC : "C:\Users\timo\Desktop\Study\MATLAB\MACAddress_mex.c";"C:\MATLAB\R2018a\extern\version\c_mexapi_version.c"
  OBJ : C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\MACAddress_mex.obj;C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\c_mexapi_version.obj
  OBJS : C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\MACAddress_mex.obj C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\c_mexapi_version.obj 
  SRCROOT : C:\Users\timo\Desktop\Study\MATLAB\MACAddress_mex
  DEF : C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\MACAddress_mex.def
  EXP : "MACAddress_mex.exp"
  LIB : "MACAddress_mex.lib"
  EXE : MACAddress_mex.mexw64
  ILK : "MACAddress_mex.ilk"
  MANIFEST : "MACAddress_mex.mexw64.manifest"
  TEMPNAME : MACAddress_mex
  EXEDIR : 
  EXENAME : MACAddress_mex
  OPTIM : -O -DNDEBUG
  LINKOPTIM : -s
  CMDLINE1_0 : C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc -c -DMATLAB_DEFAULT_RELEASE=R2017b  -DUSE_MEX_CMD   -m64 -DMATLAB_MEX_FILE  -I"C:\MATLAB\R2018a/extern/include" -I"C:\MATLAB\R2018a/simulink/include" -I"C:\MATLAB\R2018a/extern\lib\win64\mingw64" -fexceptions -fno-omit-frame-pointer -O -DNDEBUG "C:\Users\timo\Desktop\Study\MATLAB\MACAddress_mex.c" -o C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\MACAddress_mex.obj
  CMDLINE1_1 : C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc -c -DMATLAB_DEFAULT_RELEASE=R2017b  -DUSE_MEX_CMD   -m64 -DMATLAB_MEX_FILE  -I"C:\MATLAB\R2018a/extern/include" -I"C:\MATLAB\R2018a/simulink/include" -I"C:\MATLAB\R2018a/extern\lib\win64\mingw64" -fexceptions -fno-omit-frame-pointer -O -DNDEBUG "C:\MATLAB\R2018a\extern\version\c_mexapi_version.c" -o C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\c_mexapi_version.obj
-------------------------------------------------------------------
Building with 'MinGW64 Compiler (C)'.
C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc -c -DMATLAB_DEFAULT_RELEASE=R2017b  -DUSE_MEX_CMD   -m64 -DMATLAB_MEX_FILE  -I"C:\MATLAB\R2018a/extern/include" -I"C:\MATLAB\R2018a/simulink/include" -I"C:\MATLAB\R2018a/extern\lib\win64\mingw64" -fexceptions -fno-omit-frame-pointer -O -DNDEBUG "C:\Users\timo\Desktop\Study\MATLAB\MACAddress_mex.c" -o C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\MACAddress_mex.obj
C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc -c -DMATLAB_DEFAULT_RELEASE=R2017b  -DUSE_MEX_CMD   -m64 -DMATLAB_MEX_FILE  -I"C:\MATLAB\R2018a/extern/include" -I"C:\MATLAB\R2018a/simulink/include" -I"C:\MATLAB\R2018a/extern\lib\win64\mingw64" -fexceptions -fno-omit-frame-pointer -O -DNDEBUG "C:\MATLAB\R2018a\extern\version\c_mexapi_version.c" -o C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\c_mexapi_version.obj
C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc -m64 -Wl,--no-undefined -shared -static -s -Wl,"C:\MATLAB\R2018a/extern/lib/win64/mingw64/exportsmexfileversion.def" C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\MACAddress_mex.obj C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\c_mexapi_version.obj   -liphlpapi  -L"C:\MATLAB\R2018a\extern\lib\win64\mingw64" -llibmx -llibmex -llibmat -lm -llibmwlapack -llibmwblas -o MACAddress_mex.mexw64
Recompile embedded version with '-DMATLAB_MEXCMD_RELEASE=R2017b'
C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc -c -DMATLAB_DEFAULT_RELEASE=R2017b  -DUSE_MEX_CMD   -m64 -DMATLAB_MEX_FILE  -I"C:\MATLAB\R2018a/extern/include" -I"C:\MATLAB\R2018a/simulink/include" -I"C:\MATLAB\R2018a/extern\lib\win64\mingw64" -fexceptions -fno-omit-frame-pointer -O -DNDEBUG "C:\MATLAB\R2018a\extern\version\c_mexapi_version.c" -o C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\c_mexapi_version.obj -DMATLAB_MEXCMD_RELEASE=R2017b
C:\ProgramData\MATLAB\SupportPackages\R2018a_1\3P.instrset\mingw_w64.instrset\bin\gcc -m64 -Wl,--no-undefined -shared -static -s -Wl,"C:\MATLAB\R2018a/extern/lib/win64/mingw64/exportsmexfileversion.def" C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\MACAddress_mex.obj C:\Users\timo\AppData\Local\Temp\mex_2118226148433_10944\c_mexapi_version.obj   -liphlpapi  -L"C:\MATLAB\R2018a\extern\lib\win64\mingw64" -llibmx -llibmex -llibmat -lm -llibmwlapack -llibmwblas -o MACAddress_mex.mexw64
MEX completed successfully.

Answer 1

[timo]

Correction : The user have to give the path to the MinGW64 lib .a file even if its in the MinGW64 standard lib directory . Thats very user unfriendly and i reported this mex behaviour to the mingw64 developers

Here is the correct command (please note that for VS2017 compiler only -l libname is enough !)

mex -v    c:\ProgramData\MATLAB\SupportPackages\R2018a\3P.instrset\mingw_w64.instrset\x86_64-w64-mingw32\lib\libiphlpapi.a MACAddress_mex.c

[Walter Roberson]

.a files should always be listed after the objects they are providing routines for. The linker involved is one pass.

[timo]

Yeah , but this is not the issue here.

[Walter Roberson]

It is when you say "here is the correct command"

[timo]

The mex command dont throw any error ...or ? Thus is correct.

[Walter Roberson]

The most recent time that I moved bathroom tissue from storage to the bathroom, I piled the rolls 7 high. None of them fell off as I carried them through two flights of stairs. Must have been the correct way of doing it.

[Jean-Claude Arbaut]

If your only concern is having to type the directory, simply use the LIBRARY_PATH environment variable.

[timo]

Do you have to do this when you use visual studio 2015 /2017 compiler?

[Jean-Claude Arbaut]

Yes, but usually you do not see it. When you start Visual Studio's command line (not the IDE, but there are similar settings in the IDE), it runs vcvars64.bat or vcvars32.bat before you get to the command line.

These files are found in the VS installation directory, and they setup many environment variables needed by the compiler. You can see the list of environment variables by typing "set" in the console (some of them are set up by Windows, most come from vcvarsNN.bat).

Now, if for some reason the compiler does not find necessary include or library files, you can update the INCLUDE and LIB environment variables (or you can pass options to the compiler and/or linker directly).