未定义的对LibSerial的依据

Question

So i'm writing a serial transmision program, and have just changed over to using C++, it been a while since I used C++ (I've been working with C recently, and before that java)

Now I need to use LibSerial, (it seems much simpler to use than C's termios)

my code is:

//gen1.cpp
#include "string2num.h" // a custom header
#include <iostream>
#include <SerialStream.h>
using namespace LibSerial;
//using namespace std;

int main(int argc, char*argv[])
{
        if (argc<2)
        {
                std::cout<<argv[0]<<"requires the device name eg \"dev/tty0\" as a parameter\nterminating.\n";
                return 1;
        }    
        SerialStream theSerialStream(argv[1]); //open the device
        return 0;
}

When I compile the output:

g++ -Wall -o gen1 gen1.cpp string2num.o
/tmp/cchPBWgx.o: In function `main':
gen1.cpp:(.text+0x121): undefined reference to `LibSerial::SerialStream::SerialStream(std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::_Ios_Openmode)'
/tmp/cchPBWgx.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[vtable for LibSerial::SerialStreamBuf]+0x24): undefined reference to `LibSerial::SerialStreamBuf::showmanyc()'
/tmp/cchPBWgx.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[vtable for LibSerial::SerialStreamBuf]+0x28): undefined reference to `LibSerial::SerialStreamBuf::xsgetn(char*, int)'
/tmp/cchPBWgx.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[vtable for LibSerial::SerialStreamBuf]+0x2c): undefined reference to `LibSerial::SerialStreamBuf::underflow()'
/tmp/cchPBWgx.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[vtable for LibSerial::SerialStreamBuf]+0x34): undefined reference to `LibSerial::SerialStreamBuf::pbackfail(int)'
/tmp/cchPBWgx.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[vtable for LibSerial::SerialStreamBuf]+0x38): undefined reference to `LibSerial::SerialStreamBuf::xsputn(char const*, int)'
/tmp/cchPBWgx.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[vtable for LibSerial::SerialStreamBuf]+0x3c): undefined reference to `LibSerial::SerialStreamBuf::overflow(int)'
collect2: ld returned 1 exit status
make: *** [gen1] Error 1

Answer 1

This is obviously the linker complaining that i cannot find the functions reference by the libserial header file. So if I look on my Linux system how the shared library is called:

$ dpkg -L libserial0
...
/usr/lib/libserial.so.0.0.0
/usr/lib/libserial.so.0

On my system this implies I would add -lserial as a g++ option (aka link with libserial.so) this would turn your compilation command into

g++ -Wall -lserial -o gen1 gen1.cpp string2num.o

Answer 2

Including the header file is not enough - you also need to link with the library that implements SerialStream. Assuming it is a static library called serstream.a (it is almost certainly actually called something else):

g++ -Wall -o gen1 gen1.cpp string2num.o serstream.a

Answer 3

old thread, but i still use Libserial. here the completed answer My working setup.

Ubuntu 18.04 g++ 7.3.0

1) Install package for libserial

apt install libserial-dev

2) check for your headers(.h) and .so files

dpkg -l libserial0
dpkg -l libserial-dev

the first command give you the directory of shared library and the second gives you the headers location.

3) Your code.

I have to change a little your code, first i delete the custom header and modifing the constuctor call to this.

SerialStream theSerialStream;

4) compile with g++

Here my compiling command

g++ -o test -I/usr/include test.cpp -L/usr/lib/x86_64-linux-gnu -lserial -lpthread

check for the -lpthread linking option, beacuse Libserial uses mutex.

Answer 4

在Ubuntu / Debian中确保你必须安装libserial-dev包并使用gcc的'-lserial'标志。