'SerialStream' does not name a type

Question

I'm using Ubuntu 14.04. I want to use libSerial for project like described here. I installed the library using sudo apt-get install libserial-dev.

I've written a little program (well, it's not really a program):

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

#define PORT "/dev/ttyUSB0"

SerialStream ardu;

using namespace std;
using namespace LibSerial;

But the compiler says: ‘SerialStream’ does not name a type

Any help?

EDIT: After placing the SerialStream ardu after the namespace-line the problem is even more strange:

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)'

Did you try placing `SerialStream ardu;` after the `using namespace LibSerial;` statement? — πάντα ῥεῖ, Aug 16 '15 at 18:19
@PEAR Your edit doesn't make anything clearer? Just try what I've told you to do, or write `LibSeria::SerialStream ardu;`. — πάντα ῥεῖ, Aug 16 '15 at 18:33
@PEAR see here please, how to fix that: http://stackoverflow.com/questions/12573816/what-is-an-undefined-reference-unresolved-external-symbol-error-and-how-do-i-fix — πάντα ῥεῖ, Aug 16 '15 at 18:37
@πάντα ῥεῖ: I'm not sure what to do... I tried the official example of the lib and the same error occured. Is this a bug in the library? — PEAR, Aug 16 '15 at 18:41
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/87105/discussion-between-pear-and--). — PEAR, Aug 16 '15 at 18:47
The problem is not worse, its fixed. What you have now is a *different* problem. :) You need to add the library to your link command. — Galik, Aug 16 '15 at 19:02
'Is this a bug in the library?' I cannot believe comments like that. — john, Aug 16 '15 at 20:12
@john: Well, I don't really assume that there is a bug in the library... but in my case the official example did not work. — PEAR, Aug 16 '15 at 20:15
Assuming you *installed* the library to a default place then `g++ main.cpp -o ArduCom -lserial` may be enough. Otherwise you may have to specify where the library is using the `-L` switch: `g++ main.cpp -o ArduCom -Wl,-rpath,/path/to/library/folder -L/path/to/library/folder -lserial`. — Galik, Aug 16 '15 at 20:21
@Galik: Would you please post this as a comment so the thread can be closed — PEAR, Aug 17 '15 at 11:50

score 1 · Accepted Answer · answered Aug 17 '15 at 14:46

First of all you have defined an object of type SerialStream from the namespace LibSerial without properly qualifying it:

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

#define PORT "/dev/ttyUSB0"

SerialStream ardu; // error this type is unqualified

using namespace std;
using namespace LibSerial;

There are a number of ways to qualify the type. One is by placing the definition after the using declaration of the namespace the type is defined in:

#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;

Another way is to qualify the typename explicitly as belonging in a specific namespace:

LibSerial::SerialStream ardu; // fully qualifies name

Having done that, your second problem is that the compiler needs to know where the libserial library is located in the file system in order to be able to link to it.

Assuming you installed the library to a default place then this maybe enough:

g++ main.cpp -o ArduCom -lserial

Otherwise you may have to specify where the library is using the -L switch:

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

The libserial library is built using Autotools so, if you built and installed it from source it provides linking instructions as part of the install process.

The instructions are somewhat like this:

----------------------------------------------------------------------
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' does not name a type

1 Answers1