using c and c++

[cklie97]

Hello there. While writing my kernel I'm now at a point where I want to use both c, because most of my code is written in it and c++, because of classes.

At the moment I use "make" to help me compiling, but I don'nt get it why the Makefile I wrote for c and c++ do not work.

Makefile

Code: Select all

SRCS = $(shell find ./code -name '*.[cppS]')
OBJS = $(addsuffix .o,$(basename $(SRCS)))

CC = gcc
CPP = g++
LD = ld

ASFLAGS = -m32
CFLAGS = -m32 -Wall -g -fno-stack-protector -nostdinc
CPPFLAGS = -m32 -Wall -g -fno-stack-protector -nostdinc
LDFLAGS = -melf_i386 -Tcode/kernel.ld

kernel: $(OBJS)
        $(LD) $(LDFLAGS) -o $@ $^

%.o: %.c
        $(CC) $(CFLAGS) -c -o $@ $^

%.o: %.cpp
        $(CPP) $(CPPFLAGS) -c -o $@ $^

%.o: %.S
        $(CC) $(ASFLAGS) -c -o $@ $^

clean:
        rm $(OBJS)

.PHONY: clean

The problem:

• My *.cpp files are not compiled (missing *.o files)

[iansjack]

Output from the make command?

[cklie97]

Make output:

gcc -m32 -Wall -g -fno-stack-protector -nostdinc -c -o code/string.o code/string.c
gcc -m32 -c -o code/int_stub.o code/int_stub.S
gcc -m32 -Wall -g -fno-stack-protector -nostdinc -c -o code/keyboard.o code/keyboard.c
gcc -m32 -Wall -g -fno-stack-protector -nostdinc -c -o code/interrupt_descriptor_table.o code/interrupt_descriptor_table.c
gcc -m32 -Wall -g -fno-stack-protector -nostdinc -c -o code/memory_manager.o code/memory_manager.c
gcc -m32 -Wall -g -fno-stack-protector -nostdinc -c -o code/global_descriptor_table.o code/global_descriptor_table.c
gcc -m32 -Wall -g -fno-stack-protector -nostdinc -c -o code/assembler.o code/assembler.c
gcc -m32 -Wall -g -fno-stack-protector -nostdinc -c -o code/main.o code/main.c
gcc -m32 -Wall -g -fno-stack-protector -nostdinc -c -o code/console.o code/console.c
gcc -m32 -c -o code/start.o code/start.S
gcc -m32 -Wall -g -fno-stack-protector -nostdinc -c -o code/shell.o code/shell.c
ld -melf_i386 -Tcode/kernel.ld -o kernel code/string.o code/int_stub.o code/keyboard.o code/interrupt_descriptor_table.o code/memory_manager.o code/global_descriptor_table.o code/assembler.o code/main.o code/console.o code/start.o code/shell.o

[gerryg400]

Code: Select all

*.[cppS]

I think this is wrong. This means *.c or *.p or *.S. It doesn't match with cpp at all.

[cklie97]

Thanks that helped. Now the *.cpp files are getting compiled.

new Makefile

SRCS = $(shell find ./code -name '*.[cS]' -or -name '*.cpp')
[...]

But now I have a problem with the linker.

Output

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ld -melf_i386 -Tcode/kernel.ld -o kernel code/string.o code/int_stub.o code/keyboard.o code/interrupt_descriptor_table.o code/memory_manager.o code/global_descriptor_table.o code/assembler.o code/main.o code/console.o code/start.o code/shell.o code/t32.o
code/main.o: In Funktion `main':
code/main.c:13: Nicht definierter Verweis auf `test'

main.c

Code: Select all

[...]
#include "t32.h"

10  int main(void)
11  {
12      init();
13      test();
14      while(1);
15      return 0;
16  }
[...]

t32.h

Code: Select all

void test();

t32.cpp

Code: Select all

#include "t32.h"

void test()
{
}

[heat]

Thanks that helped. Now the *.cpp files are getting compiled.

new Makefile

SRCS = $(shell find ./code -name '*.[cS]' -or -name '*.cpp')
[...]

But now I have a problem with the linker.

Output

Code: Select all

ld -melf_i386 -Tcode/kernel.ld -o kernel code/string.o code/int_stub.o code/keyboard.o code/interrupt_descriptor_table.o code/memory_manager.o code/global_descriptor_table.o code/assembler.o code/main.o code/console.o code/start.o code/shell.o code/t32.o
code/main.o: In Funktion `main':
code/main.c:13: Nicht definierter Verweis auf `test'

main.c

Code: Select all

[...]
#include "t32.h"

10  int main(void)
11  {
12      init();
13      test();
14      while(1);
15      return 0;
16  }
[...]

t32.h

Code: Select all

void test();

t32.cpp

Code: Select all

#include "t32.h"

void test()
{
}

I'm not sure if you know what C++ name decoration/mangling is... i suggest you learn more about the linking process.

[Roman]

Don't forget C++ names are mangled to contain type information. If you want a C++ function to be callable from C, you need to declare it with extern "C".

[Octocontrabass]

Code: Select all

CC = gcc
CPP = g++

You should be using a cross-compiler, too.