mingw32无法链接到库

Question

Alright, so this is an interesting one that has been tested on two versions of mingw*, it's probably user error but google failed me.

I still can't build more complex projects correctly even though they ought to, for example - let's take the example included in the newton physics engine sdk, it's a pretty simple program.

first we build newton using the included makefile (as specifically recommended by a maintainer because cmake kept outputting broken makefiles), this is simple enough - it outputs a perfectly reasonable .a file.

these are the flags in the newton makefile

-c -Wall -Wno-strict-aliasing  -DPTW32_BUILD -DPTW32_STATIC_LIB -D_NEWTON_STATIC_LIB -D_MINGW_32_VER -m32 -O2 -fpic -g -msse -msse3 -msse4 -mfpmath=sse -ffloat-store -ffast-math -freciprocal-math -funsafe-math-optimizations -fsingle-precision-constant -I$(DG_INCLUDED_PATH) -I$(DG_INCLUDED_PHYSICS_PATH) -I$(DG_INCLUDED_MESH_PATH) -I$(DG_INCLUDED_OPENCL_PATH)

however, if I then want to actually build the example then we get some slight problems.

g++ -march=core2 -o out.exe ex.cpp -g -m32 -lNewton 2>&1 | tee build.log

And what do we get? linker errors. undefined references everywhere because the name mangling doesn't seem to match

I'm probably just overlooking something obvious but I'm a tad lost as to what that obvious thing would be.

*g++.exe (TDM-2 mingw32) 4.4.1 and g++.exe (GCC) 5.3.0 so that would be TDM mingw g++ 4.4.1 and vanilla mingw 5.3.0

here's the makefile (you may notice some minor tweaks to the makefile from the default mingw32 makefile, that is because originally it didn't build at all until I fixed some whitespace problems):

#*******************************************************
#
# Newton game dynamics 
# copy right by Julio Jerez 2002 - 2012
#
#*******************************************************
#
# Generic makefile 
# this make file generate the libraries: 
# dg, physics, and newton
#
#*******************************************************  


# ******************************************************
#
# dg low level library
#
# ******************************************************
DG_INCLUDED_PATH = ../../source/core
DG_PATH = $(DG_INCLUDED_PATH)/
DG_SRCS = \
    $(DG_PATH)dgAABBPolygonSoup.cpp \
    $(DG_PATH)dgAsyncThread.cpp \
    $(DG_PATH)dgConvexHull3d.cpp \
    $(DG_PATH)dgConvexHull4d.cpp \
    $(DG_PATH)dg.cpp \
    $(DG_PATH)dgCRC.cpp \
    $(DG_PATH)dgDebug.cpp \
    $(DG_PATH)dgDelaunayTetrahedralization.cpp \
    $(DG_PATH)dgGeneralMatrix.cpp \
    $(DG_PATH)dgGeneralVector.cpp \
    $(DG_PATH)dgGoogol.cpp \
    $(DG_PATH)dgIntersections.cpp \
    $(DG_PATH)dgMatrix.cpp \
    $(DG_PATH)dgMemory.cpp \
    $(DG_PATH)dgMutexThread.cpp \
    $(DG_PATH)dgNode.cpp \
    $(DG_PATH)dgPolygonSoupBuilder.cpp \
    $(DG_PATH)dgPolyhedra.cpp \
    $(DG_PATH)dgPolyhedraMassProperties.cpp \
    $(DG_PATH)dgQuaternion.cpp \
    $(DG_PATH)dgRandom.cpp \
    $(DG_PATH)dgRefCounter.cpp \
    $(DG_PATH)dgRef.cpp \
    $(DG_PATH)dgSmallDeterminant.cpp \
    $(DG_PATH)dgSPDMatrix.cpp \
    $(DG_PATH)dgObb.cpp \
    $(DG_PATH)dgThread.cpp \
    $(DG_PATH)dgThreadHive.cpp \
    $(DG_PATH)dgTree.cpp \
    $(DG_PATH)dgTypes.cpp


# ******************************************************
#
# Physics engine files
#
# ******************************************************
DG_INCLUDED_PHYSICS_PATH = ../../source/physics
DG_PHYSICS_PATH = $(DG_INCLUDED_PHYSICS_PATH)/
DG_PHYSICS_SRCS = \
    $(DG_PHYSICS_PATH)dgBody.cpp \
    $(DG_PHYSICS_PATH)dgDynamicBody.cpp \
    $(DG_PHYSICS_PATH)dgKinematicBody.cpp \
    $(DG_PHYSICS_PATH)dgBallConstraint.cpp \
    $(DG_PHYSICS_PATH)dgBilateralConstraint.cpp \
    $(DG_PHYSICS_PATH)dgBody.cpp \
    $(DG_PHYSICS_PATH)dgDynamicBody.cpp \
    $(DG_PHYSICS_PATH)dgKinematicBody.cpp \
    $(DG_PHYSICS_PATH)dgBodyMasterList.cpp \
    $(DG_PHYSICS_PATH)dgBroadPhase.cpp \
    $(DG_PHYSICS_PATH)dgCollisionBox.cpp \
    $(DG_PHYSICS_PATH)dgCollisionBVH.cpp \
    $(DG_PHYSICS_PATH)dgCollisionCapsule.cpp \
    $(DG_PHYSICS_PATH)dgCollisionChamferCylinder.cpp \
    $(DG_PHYSICS_PATH)dgCollisionCompoundFractured.cpp \
    $(DG_PHYSICS_PATH)dgCollisionCompound.cpp \
    $(DG_PHYSICS_PATH)dgCollisionCone.cpp \
    $(DG_PHYSICS_PATH)dgCollisionConvex.cpp \
    $(DG_PHYSICS_PATH)dgCollisionConvexHull.cpp \
    $(DG_PHYSICS_PATH)dgCollisionConvexPolygon.cpp \
    $(DG_PHYSICS_PATH)dgCollision.cpp \
    $(DG_PHYSICS_PATH)dgCollisionCylinder.cpp \
    $(DG_PHYSICS_PATH)dgCollisionDeformableClothPatch.cpp \
    $(DG_PHYSICS_PATH)dgCollisionDeformableSolidMesh.cpp \
    $(DG_PHYSICS_PATH)dgCollisionDeformableMesh.cpp \
    $(DG_PHYSICS_PATH)dgCollisionHeightField.cpp \
    $(DG_PHYSICS_PATH)dgCollisionInstance.cpp \
    $(DG_PHYSICS_PATH)dgCollisionMesh.cpp \
    $(DG_PHYSICS_PATH)dgCollisionNull.cpp \
    $(DG_PHYSICS_PATH)dgCollisionScene.cpp \
    $(DG_PHYSICS_PATH)dgCollisionSphere.cpp \
    $(DG_PHYSICS_PATH)dgCollisionTaperedCapsule.cpp \
    $(DG_PHYSICS_PATH)dgCollisionTaperedCylinder.cpp \
    $(DG_PHYSICS_PATH)dgCollisionUserMesh.cpp \
    $(DG_PHYSICS_PATH)dgConstraint.cpp \
    $(DG_PHYSICS_PATH)dgContact.cpp \
    $(DG_PHYSICS_PATH)dgCorkscrewConstraint.cpp \
    $(DG_PHYSICS_PATH)dgDeformableBody.cpp \
    $(DG_PHYSICS_PATH)dgDeformableContact.cpp \
    $(DG_PHYSICS_PATH)dgHingeConstraint.cpp \
    $(DG_PHYSICS_PATH)dgNarrowPhaseCollision.cpp \
    $(DG_PHYSICS_PATH)dgSlidingConstraint.cpp \
    $(DG_PHYSICS_PATH)dgUniversalConstraint.cpp \
    $(DG_PHYSICS_PATH)dgUpVectorConstraint.cpp \
    $(DG_PHYSICS_PATH)dgUserConstraint.cpp \
    $(DG_PHYSICS_PATH)dgWorld.cpp \
    $(DG_PHYSICS_PATH)dgDeformableBodiesUpdate.cpp \
    $(DG_PHYSICS_PATH)dgWorldDynamicsParallelSolver.cpp \
    $(DG_PHYSICS_PATH)dgWorldDynamicsSimpleSolver.cpp \
    $(DG_PHYSICS_PATH)dgWorldDynamicUpdate.cpp


# ******************************************************
#
# mesh gemotry 
#
# ******************************************************
DG_INCLUDED_MESH_PATH = ../../source/meshUtil
DG_MESH_PATH = $(DG_INCLUDED_MESH_PATH)/
DG_MESH_SRCS = \
    $(DG_MESH_PATH)dgMeshEffect1.cpp \
    $(DG_MESH_PATH)dgMeshEffect2.cpp \
    $(DG_MESH_PATH)dgMeshEffect3.cpp \
    $(DG_MESH_PATH)dgMeshEffect4.cpp \
    $(DG_MESH_PATH)dgMeshEffect5.cpp \
    $(DG_MESH_PATH)dgMeshEffect6.cpp 

# ******************************************************
#
# open cl 
#
# ******************************************************
DG_INCLUDED_OPENCL_PATH = ../../source/openCL
DG_OPENCL_PATH = $(DG_INCLUDED_OPENCL_PATH)/
#DG_OPENCL_SRCS = \
#   $(DG_OPENCL_PATH)dgOpencl.cpp \
#   $(DG_OPENCL_PATH)dgOpenclInstance.cpp \
#   $(DG_OPENCL_PATH)dgOpenclBroadPhase.cpp



# ******************************************************
#
# Newton engine files
#g++ -shared -o libNewton.dll libNewton.a
# ******************************************************
DG_INCLUDED_NEWTON_PATH = ../../source/newton
DG_NEWTON_PATH = $(DG_INCLUDED_NEWTON_PATH)/
DG_NEWTON_SRCS = \
    $(DG_NEWTON_PATH)Newton.cpp \
    $(DG_NEWTON_PATH)NewtonClass.cpp

# ******************************************************
#
# Allsource files
#
# ******************************************************
ALL_SRC_FILES = $(DG_SRCS) $(DG_PHYSICS_SRCS) $(DG_OPENCL_SRCS) $(DG_MESH_SRCS) $(DG_NEWTON_SRCS)
DG_OBJ_FILES = $(ALL_SRC_FILES:.cpp=.o)

COMPILER = gcc

# mingw options  gcc 4.4.2
#CPU_FLAGS = -m32 -O0 -fPIC -g -msse -msse2 -mfpmath=sse 
#CPU_FLAGS = -m32 -O0 -fPIC -g -msse -msse4.1 -mfpmath=sse 
#CPU_FLAGS = -m32 -O2 -fpic -g -msse -msse4.1 -mfpmath=sse -ffloat-store -ffast-math -freciprocal-math -funsafe-math-optimizations -fsingle-precision-constant
CPU_FLAGS = -m32 -O2 -fpic -g -msse -msse3 -msse4 -mfpmath=sse -ffloat-store -ffast-math -freciprocal-math -funsafe-math-optimizations -fsingle-precision-constant

FLAGS  = -Wall -Wno-strict-aliasing  -DPTW32_BUILD -DPTW32_STATIC_LIB -D_NEWTON_STATIC_LIB -D_MINGW_32_VER $(CPU_FLAGS) -I$(DG_INCLUDED_PATH) -I$(DG_INCLUDED_PHYSICS_PATH) -I$(DG_INCLUDED_MESH_PATH) -I$(DG_INCLUDED_OPENCL_PATH)

.SUFFIXES : .o .cpp
.cpp.o :
    $(COMPILER) $(FLAGS) -o $@ $<

# main target
engine : libNewton.a


# clean all objects target
clean :
    rm $(DG_OBJ_FILES)
    touch $(ALL_SRC_FILES)

# libraries targets
libNewton.a : $(DG_OBJ_FILES)
    ar r $@ $?
    strip -g -S -d -v libNewton.a -o libNewton.a
    cp libNewton.a ../../../packages/mingw32/libNewton.a
    cp ../../source/newton/Newton.h ../../../packages/mingw32/Newton.h
#   $(COMPILER) -shared -Wl,-soname,libNewton.dll $? -o libNewton.dll 
#   cp libNewton.dll ../../../packages/mingw32/libNewton.dll
    #sudo cp libNewton.dll /usr/lib

and the linker errors I get if I build without -c (all of the newton functionality is undefined, this is not a surprise to anyone since that's what -c is meant to do but the fact that it breaks for even the simplest of test cases implies something is wrong)

C:\Users\Thunder\AppData\Local\Temp\cchfxWSh.o: In function `Z20CreateBackgroundBodyP11NewtonWorld':
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:17: undefined reference to `_imp__NewtonCreateTreeCollision'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:20: undefined reference to `_imp__NewtonTreeCollisionBeginBuild'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:23: undefined reference to `_imp__NewtonTreeCollisionAddFace'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:26: undefined reference to `_imp__NewtonTreeCollisionEndBuild'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:29: undefined reference to `dGetIdentityMatrix()'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:30: undefined reference to `_imp__NewtonCreateDynamicBody'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:33: undefined reference to `_imp__NewtonDestroyCollision'
C:\Users\Thunder\AppData\Local\Temp\cchfxWSh.o: In function `ApplyGravity':
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:45: undefined reference to `_imp__NewtonBodyGetMassMatrix'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:47: undefined reference to `_imp__NewtonBodySetForce'
C:\Users\Thunder\AppData\Local\Temp\cchfxWSh.o: In function `Z18CreateFreeFallBallP11NewtonWorld':
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:53: undefined reference to `_imp__NewtonCreateSphere'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:56: undefined reference to `dGetIdentityMatrix()'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:58: undefined reference to `_imp__NewtonCreateDynamicBody'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:61: undefined reference to `_imp__NewtonBodySetForceAndTorqueCallback'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:65: undefined reference to `_imp__NewtonBodySetMassProperties'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:68: undefined reference to `_imp__NewtonBodySetLinearDamping'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:71: undefined reference to `_imp__NewtonDestroyCollision'
C:\Users\Thunder\AppData\Local\Temp\cchfxWSh.o: In function `main':
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:79: undefined reference to `_imp__NewtonCreate'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:86: undefined reference to `_imp__NewtonInvalidateCache'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:90: undefined reference to `_imp__NewtonUpdate'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:93: undefined reference to `_imp__NewtonBodyGetMatrix'
C:\Users\Thunder\Documents\projects\libproto framework\src/ex.cpp:98: undefined reference to `_imp__NewtonDestroy'
collect2.exe: error: ld returned 1 exit status

Answer 1

Your problem is simple.

the -c switch of gcc does only compilation step without linking and producing an executable module.

The fact that you instructed gcc to write an output to a file with .exe extension makes no special meaning to the gcc .

So you are just trying to execute the object file, so Winodws complains.

---

I assume that you mistyped the last arguments in the commands shown and they should read as hello_world.c

Answer 2

Alright, I finally narrowed down the root cause of not being able to compile or link anything.

The cause being that the two libraries I already linked successfully are written to be C++98 compatible - these build and link fine. However newton dynamics and box2D that are also used by my framework [which is what I'm having trouble porting] are both dependent on C++11 or higher.

This took a while to find because it never occurred to me that the problem may be with just the C++11 subset of the toolchain, I noticed it entirely coincidentally when I noticed that I can't build even the simplest c++11 projects (projects only using nullptr), if I were using g++ 4.5 or older this would be expected but it's been available since 4.6 and up.

Thus we get to the troubleshooting, I take the hello world app (pretty standard but code included anyway) and build it using

#include <iostream>

using namespace std;

int main()
{
    cout << "Hello world!" << endl;
    return 0;
}

g++.exe -Wall -fexceptions -g -O2 -c gcc530_sanitytest\\main.cpp -o obj\\Debug\\main.o

This works very well.

if we then try with

g++.exe -Wall -fexceptions -std=c++11 -g -O2 -c gcc530_sanitytest\\main.cpp -o obj\\Debug\\main.o

then we get a slew of errors

namely:

||=== Build: Debug in gcc530_sanitytest (compiler: GNU GCC Compiler) ===|
c:\mingw\include\sys\stat.h|173|error: '_dev_t' does not name a type|
c:\mingw\include\sys\stat.h|173|error: '_ino_t' does not name a type|
c:\mingw\include\sys\stat.h|173|error: '_mode_t' does not name a type|
c:\mingw\include\sys\stat.h|173|error: '_dev_t' does not name a type|
c:\mingw\include\sys\stat.h|173|error: '_off_t' does not name a type|
c:\mingw\include\sys\stat.h|173|error: 'time_t' does not name a type|
c:\mingw\include\sys\stat.h|173|error: 'time_t' does not name a type|
c:\mingw\include\sys\stat.h|173|error: 'time_t' does not name a type|
c:\mingw\include\sys\stat.h|180|error: '_dev_t' does not name a type|
c:\mingw\include\sys\stat.h|180|error: '_ino_t' does not name a type|
c:\mingw\include\sys\stat.h|180|error: '_mode_t' does not name a type|
c:\mingw\include\sys\stat.h|180|error: '_dev_t' does not name a type|
c:\mingw\include\sys\stat.h|180|error: '_off_t' does not name a type|
c:\mingw\include\sys\stat.h|180|error: 'time_t' does not name a type|
c:\mingw\include\sys\stat.h|180|error: 'time_t' does not name a type|
c:\mingw\include\sys\stat.h|180|error: 'time_t' does not name a type|
c:\mingw\include\sys\stat.h|188|error: '_dev_t' does not name a type|
c:\mingw\include\sys\stat.h|188|error: '_ino_t' does not name a type|
c:\mingw\include\sys\stat.h|188|error: '_mode_t' does not name a type|
c:\mingw\include\sys\stat.h|188|error: '_dev_t' does not name a type|
c:\mingw\include\sys\stat.h|188|error: '__off64_t' does not name a type|
c:\mingw\include\sys\stat.h|188|error: 'time_t' does not name a type|
c:\mingw\include\sys\stat.h|188|error: 'time_t' does not name a type|
c:\mingw\include\sys\stat.h|188|error: 'time_t' does not name a type|
c:\mingw\include\sys\stat.h|195|error: '_dev_t' does not name a type|
c:\mingw\include\sys\stat.h|195|error: '_ino_t' does not name a type|
c:\mingw\include\sys\stat.h|195|error: '_mode_t' does not name a type|
c:\mingw\include\sys\stat.h|195|error: '_dev_t' does not name a type|
c:\mingw\include\sys\stat.h|195|error: '__off64_t' does not name a type|
c:\mingw\include\sys\stat.h|195|error: '__time64_t' does not name a type|
c:\mingw\include\sys\stat.h|195|error: '__time64_t' does not name a type|
c:\mingw\include\sys\stat.h|195|error: '__time64_t' does not name a type|
c:\mingw\include\io.h|335|error: 'time_t' does not name a type|
c:\mingw\include\io.h|335|error: 'time_t' does not name a type|
c:\mingw\include\io.h|335|error: 'time_t' does not name a type|
c:\mingw\include\io.h|336|error: 'time_t' does not name a type|
c:\mingw\include\io.h|336|error: 'time_t' does not name a type|
c:\mingw\include\io.h|336|error: 'time_t' does not name a type|
c:\mingw\include\io.h|362|error: '__time64_t' does not name a type|
c:\mingw\include\io.h|362|error: '__time64_t' does not name a type|
c:\mingw\include\io.h|362|error: '__time64_t' does not name a type|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\cwchar|146|error: '::fwide' has not been declared|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\cwchar|153|error: '::mbsinit' has not been declared|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\cwchar|198|error: '::wmemcmp' has not been declared|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\cwchar|199|error: '::wmemcpy' has not been declared|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\cwchar|200|error: '::wmemmove' has not been declared|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\cwchar|201|error: '::wmemset' has not been declared|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\cwchar|208|error: '::wmemchr' has not been declared|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\cwchar||In function 'wchar_t* std::wmemchr(wchar_t*, wchar_t, std::size_t)':|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\cwchar|229|error: invalid conversion from 'const wchar_t*' to 'wchar_t*' [-fpermissive]|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\cwchar|228|note:   initializing argument 1 of 'wchar_t* std::wmemchr(wchar_t*, wchar_t, std::size_t)'|
c:\mingw\lib\gcc\mingw32\5.3.0\include\c++\bits\char_traits.h|353|error: 'wmemcmp' was not declared in this scope|
||More errors follow but not being shown.|
||Edit the max errors limit in compiler options...|
||=== Build failed: 50 error(s), 0 warning(s) (0 minute(s), 0 second(s)) ===|

this thus leads to the obvious conclusion that the build environment is broken, this answers the question nicely enough as far as I'm concerned - still giving serge the confirmed answer because of reminding/educating me on what -c does (although it was not the root cause).

perhaps this is the way mingw is designed to work but then it's broken by design (somehow I doubt that however, rather I see no reason why they would intentionally break C++11)