'SerialStream'不命名类型

'SerialStream' does not name a type

本文关键字：类型 SerialStream      更新时间：2023-10-16

我使用的是Ubuntu 14.04。我想在这里描述的项目中使用libSerial。我使用sudo apt-get install libserial-dev安装了这个库。

我写了一个小程序(好吧，它不是一个真正的程序):

#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

帮忙吗?

编辑:将SerialStream ardu放在名称空间行之后，问题就更加奇怪了:

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)'

首先，您从名称空间LibSerial定义了一个类型为SerialStream的对象，而没有正确限定它:

#include "SerialStream.h"
#include <iostream>
#define PORT "/dev/ttyUSB0"
SerialStream ardu; // error this type is unqualified
using namespace std;
using namespace LibSerial;

有许多方法可以限定类型。一种是将定义放在之后，使用名称空间的声明类型定义在:

#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;

另一种方法是显式地限定类型名属于特定的命名空间:

LibSerial::SerialStream ardu; // fully qualifies name

这样做了，你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。

假设您将库安装到默认位置，那么这可能足够了:

g++ main.cpp -o ArduCom -lserial

否则，您可能必须使用-L开关指定库的位置:

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，它会提供链接指令，作为install过程的一部分。

指令有点像这样:

----------------------------------------------------------------------
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.
----------------------------------------------------------------------
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