Ulrich Eckhardt wrote:
Martin Jørgensen wrote:
I just made my first C++/C combined project and it works on windows. Now
I want it to work on linux. So I have changed main.c to main.cpp
I don't think you mean that, but anyways: there is no reason to name things
differently in order to compile them under Linux.
Oh, I think this might be a misunderstanding because also on windows,
the main.c is now called main.cpp - if that was what you were referring
to...... I read that it was necessary to have the main() function in
C++, in order to mix those languages...
and also have a new C++-function in the file: output_energy.cpp. The
rest are C-functions.
How should the make-file be modified? I know that main must be processed
by a C++-compiler so I changed CC = gcc to CC = g++ in the makefile
below
Nope, that's wrong:
1. You don't set CC in the makefile, 'make' knows quite well the name of
the C compiler and this disallows overriding by the user (e.g. to select a
specific version).
Thanks.
2. The C++ compiler is CXX and also known to 'make'
.c.o:
$(RM) $@
@ #
$(CC) -c $(CFLAGS) $(SRC)/$*.c
# similarly for C++
.cpp.o:
$(CXX) $(CXXFLAGS) -c $(SRC)/$*.c
However, I think the placeholder for the input file is $< (i.e. the one
currently being compiled), see the manual.
The "gnu make manual" called make.pdf from www.gnu.org, right? I
downloaded it...
PROTO_DEFINES = -DFUNCPROTO=15 -DNARROWPROTO
STD_DEFINES = -Dlinux -D__i386__ -D_POSIX_C_SOURCE=199309L
^^^^^^^^^^^^^^^^^^^
Don't do that either, it make the makefile non-portable and those (or
similar ones) should be defined by the compiler (assuming you are using it
under Linux and on an x86 architecture).
I just stole it from somewhere, but I don't know what it means... Now I
deleted it completely.
CFLAGS = $(PROTO_DEFINES) $(STD_DEFINES) -g -W -Wall -ansi
The -W is deprecated and now called -Wextra, IIRC.
I think you're right...
simulate: $(OBJ)
$(RM) $@
$(CC) -o $@ -g -W -Wall -ansi -pedantic -Wformat-nonliteral[...]
Wait a second, are you repeating all the warning settings here? Use CFLAGS
Erhm.... Perhaps I do... I wasn't really sure what this makefile did in
the first place :-)
instead. Anyhow, this is the linker stage, and things like '-ansi' only
affect compilation so this doesn't make sense here anyway. Also, if you
are linking a C++ program, you need to use CXX for that.
Hmm. Okay. So in the linker stage I need something else than CFLAGS. And
since main() is a C++ function I need CXX to do the linking of all .o
files, I guess...
-snip (error messages) -
....
....
This is a result of compiling C code with a C++ compiler. C allows
converting a void pointer to any other pointer without an explicit cast,
C++ with its stricter type safety doesn't. Use a C compiler or fix the
code. Or, in general, don't blindly use a C++ compiler, there is no reason
for it.
Got it.
What do I do? I think I need to tell my makefile that most of the files
should be compiled by a C-compiler (gcc?) and main.cpp and the other
.cpp files should be compiled with g++?
Right, I hope I showed you how to separate those.
Yep, I think you helped me a lot... I think I'm very close to being able
to compile my newly transformed C++ (originally a C)-program:
--- new makefile ---
RM = rm -f
SRC = ./
SYS_LIBRARIES = -lm
CFLAGS = -g -c -Wextra -Wall -ansi -pedantic
-Wformat-nonliteral -Wcast-align -Wpointer-arith -Wbad-function-cast
-Wmissing-prototypes -Wstrict-prototypes -Wmissing-declarations -Winline
-Wundef -Wnested-externs -Wcast-qual -Wshadow -Wconversion
-Wwrite-strings -Wno-conversion -ffloat-store -O0
CXXFLAGS = -g -c -O0 -Wall
# output program (executable file name)
PGM = simulate
# files that must be made by C-compiler (CC)
OBJ_C = \
array_functions.o \
band_solve.o \
check_errors.o \
import_data.o \
memory_functions.o \
mesh_functions.o \
polymesh.o \
porosities.o \
read_materials.o \
result_output.o
# files that must be made by C++-compiler (CXX)
OBJ_CPP = \
main.o \
output_energy.o
simulate: $(OBJ_C) $(OBJ_CPP)
$(RM) $@
$(CC) -o $@ $(CFLAGS) $(OBJ_C) $(LIBPATH) $(SYS_LIBRARIES)
Solverlib.a
$(CXX) -o $@ $(CXXFLAGS) $(OBJ_CPP) $(LIBPATH) $(SYS_LIBRARIES)
Solverlib.a
etags `find -iname "*.c"` `find -iname "*.cpp"` `find -iname "*.h"`
clean::
$(RM) simulate *.CKP *.ln *.BAK *.bak *.o *.u a.out core errs
,* *~ .emacs_* tags TAGS make.log MakeOut "#"*
----
So I cleaned up a lot... Was also tired of not understanding what was in
it... When I try to compile my C++ program (using many C-functions) I get:
---- output ---
....
....
....
cc -g -c -Wextra -Wall -ansi -pedantic -Wformat-nonliteral -Wcast-align
-Wpointer-arith -Wbad-function-cast -Wmissing-prototypes
-Wstrict-prototypes -Wmissing-declarations -Winline -Wundef
-Wnested-externs -Wcast-qual -Wshadow -Wconversion -Wwrite-strings
-Wno-conversion -ffloat-store -O0 -c -o result_output.o result_output.c
g++ -g -c -O0 -Wall -c -o main.o main.cpp
g++ -g -c -O0 -Wall -c -o output_energy.o output_energy.cpp
rm -f simulate
cc -o simulate -g -c -Wextra -Wall -ansi -pedantic -Wformat-nonliteral
-Wcast-align -Wpointer-arith -Wbad-function-cast -Wmissing-prototypes
-Wstrict-prototypes -Wmissing-declarations -Winline -Wundef
-Wnested-externs -Wcast-qual -Wshadow -Wconversion -Wwrite-strings
-Wno-conversion -ffloat-store -O0 array_functions.o band_solve.o
check_errors.o import_data.o memory_functions.o mesh_functions.o
polymesh.o porosities.o read_materials.o result_output.o -lm Solverlib.a
cc: array_functions.o: linker input file unused because linking not done
cc: band_solve.o: linker input file unused because linking not done
cc: check_errors.o: linker input file unused because linking not done
..... etc......
... (more lines with linking not done)
...
----
So, what is the (hopefully finally?) push in the right direction I need
now? Comments/suggestions are appreciated. I also would like to have the
g++ warning level turned up to the "ultimate maximum level", if possible.
Best regards
Martin Jørgensen
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