Question

我正在使用Ubuntu 14.04。我想将libSerial用于描述here之类的项目。我使用sudo apt-get install libserial-dev安装了库。

我写了一个小程序（好吧，它不是真正的程序）：

#include "SerialStream.h"
#include <iostream>

#define PORT "/dev/ttyUSB0"

SerialStream ardu;

using namespace std;
using namespace LibSerial;

但是编译器说：‘SerialStream’ does not name a type

任何帮助？

编辑：在命名空间行之后放置SerialStream ardu之后问题更加奇怪：

g++ main.cpp -o ArduCom
/tmp/ccNzzINg.o: In Funktion `main':
main.cpp:(.text+0x7a): not defined reference to `LibSerial::SerialStream::Open(std::string, std::_Ios_Openmode)'
main.cpp:(.text+0x12d): not defined reference to `LibSerial::SerialStream::SetBaudRate(LibSerial::SerialStreamBuf::BaudRateEnum)'
main.cpp:(.text+0x181): not defined reference to `LibSerial::SerialStream::SetCharSize(LibSerial::SerialStreamBuf::CharSizeEnum)'
main.cpp:(.text+0x1d5): not defined reference to `LibSerial::SerialStream::SetParity(LibSerial::SerialStreamBuf::ParityEnum)'
main.cpp:(.text+0x229): not defined reference to `LibSerial::SerialStream::SetNumOfStopBits(short)'
main.cpp:(.text+0x27d): not defined reference to `LibSerial::SerialStream::SetFlowControl(LibSerial::SerialStreamBuf::FlowControlEnum)'
/tmp/ccNzzINg.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[_ZTVN9LibSerial15SerialStreamBufE]+0x48): not defined reference to `LibSerial::SerialStreamBuf::showmanyc()'
/tmp/ccNzzINg.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[_ZTVN9LibSerial15SerialStreamBufE]+0x50): not defined reference to `LibSerial::SerialStreamBuf::xsgetn(char*, long)'
/tmp/ccNzzINg.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[_ZTVN9LibSerial15SerialStreamBufE]+0x58): not defined reference to `LibSerial::SerialStreamBuf::underflow()'
/tmp/ccNzzINg.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[_ZTVN9LibSerial15SerialStreamBufE]+0x68): not defined reference to `LibSerial::SerialStreamBuf::pbackfail(int)'
/tmp/ccNzzINg.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[_ZTVN9LibSerial15SerialStreamBufE]+0x70): not defined reference to `LibSerial::SerialStreamBuf::xsputn(char const*, long)'
/tmp/ccNzzINg.o:(.rodata._ZTVN9LibSerial15SerialStreamBufE[_ZTVN9LibSerial15SerialStreamBufE]+0x78): not defined reference to `LibSerial::SerialStreamBuf::overflow(int)'

Answer 1

首先，您已经从命名空间SerialStream定义了LibSerial类型的对象，而没有正确地限定：

#include "SerialStream.h"
#include <iostream>

#define PORT "/dev/ttyUSB0"

SerialStream ardu; // error this type is unqualified

using namespace std;
using namespace LibSerial;

有很多方法可以限定类型。一种方法是将定义

#include "SerialStream.h"
#include <iostream>

#define PORT "/dev/ttyUSB0"

using namespace std;
using namespace LibSerial;

// qualified by the compiler searching through the
// declared namespaces and finding it in `namespace LibSerial`.

SerialStream ardu;

另一种方法是将typename明确限定为属于特定命名空间的

：

LibSerial::SerialStream ardu; // fully qualifies name

完成此操作后，您的第二个问题是编译器需要知道libserial库在文件系统中的位置，以便能够链接到它。

假设您已将库安装到默认位置，那么这可能就足够了：

g++ main.cpp -o ArduCom -lserial

否则，您可能必须指定库使用-L开关的位置：

g++ main.cpp -o ArduCom -Wl,-rpath,/path/to/library/folder -L/path/to/library/folder -lserial

libserial库是使用Autotools构建的，因此，如果您从源代码构建并安装它，则会在 install 过程中提供链接说明。

说明书有点像这样：

---------------------------------------------------------------------- Libraries have been installed in: /path/to/libserial/lib If you ever happen to want to link against installed libraries in a given directory, LIBDIR, you must either use libtool, and specify the full pathname of the library, or use the '-LLIBDIR' flag during linking and do at least one of the following: - add LIBDIR to the 'LD_LIBRARY_PATH' environment variable during execution - add LIBDIR to the 'LD_RUN_PATH' environment variable during linking - use the '-Wl,-rpath -Wl,LIBDIR' linker flag - have your system administrator add LIBDIR to '/etc/ld.so.conf' See any operating system documentation about shared libraries for more information, such as the ld(1) and ld.so(8) manual pages. ----------------------------------------------------------------------

'SerialStream'没有命名类型

1 个答案: