first of all root 5.17/05 x86_64 GNU/Linux g++ 3.4.5
I’m writing a gui to make it simpler for other people than me to use some software I’ve written to do some tests on detectors. In the test software there is a class with methods whose output is given in a cout-like fashion but to any ostream (I have a
"std::ostream &aostream=std::cout" in the declaration of each method). What I would like to do is to give as an “ostream” a TGTextView that I use as output in my GUI. One why of doing this is using a ostringstream object and then copy the content line by line, but this does not work if I want the output statements in my methods to appear in the TGTextView as if they were written to std::cout in a terminal. Is the question clear?
Any ideas?
There are methods LoadBuffer(const char* txtbuf) and LoadFile((const char* fname, long startpos = 0, long length = -1) that may help you to get what you want. It will be better if you provide a simple running example which shows what you have and what you need (please make it as simple as possible).
A small script that illustrates my question. When the button is pressed the numbers 0-9 is first written to std::cout with a 700ms delay between the numbers. Then they are written in the TextView. Note the difference, when written to the TextView one has to wait ~7s then is it all written at the same time. This is not what I want, I would like the same behaviour in both cases, i.e. a number is written to textview, one waits 700ms the next is written and so on.
It is not an option to let the help-class in my example see the TGTextView object: The only interface I have is an ostream-object.
the modified script you sent does not quite work in my application, I’m really limited to using only an ostream object as communication! So I tried to implement something that works the way I would like it to:
class TGTextViewStream : public TGTextView, public std::ostream
{
.
}
This implementation of mine almost works, but not quite, and I’m sort on the edge om my c++ knowledge here. Maybe someone can help? I include the a small set of files to test what I have done. Test it like
Notice that my TextViewStream works if used directly but not if passad as an argument to a class method (which is what I would like to do). In this test the result is that nothing is written to the TGText buffer. In my real application I get a crash: Stack strace:
0x00000039d478eb44 in waitpid () from /lib64/tls/libc.so.6 #1 0x00000039d47398df in do_system () from /lib64/tls/libc.so.6 #2 0x0000002a957913d7 in TUnixSystem::StackTrace ()
from /home/jljungva/root/lib/root/libCore.so #3 0x0000002a9578e198 in TUnixSystem::DispatchSignals ()
from /home/jljungva/root/lib/root/libCore.so #4 #5 0x00000039d708552d in std::operator<< <std::char_traits > () <- ! I think
from /usr/lib64/libstdc++.so.6 #6 0x0000002a97c7083b in TNT2::tnt2::ReadCalibration (this=0xb761b8,
inputstream=Variable “inputstream” is not available.
) at tnt2.cpp:855
the stream operators are non-virtual, so you cannot overload them in a derived class and have them called through the base class pointer / reference. Instead you’ll have to work on the buffer; see e.g. http://spec.winprog.org/streams/ Make yourself a cup of coffee before reading that Good luck!
Thanks, I sort of expected that I was bit too optimistic;( Luckly I got coffee and the weather in the Paris region is really bad! Maybe I get around to make a std::istream-object as well…
Anyway, I post the code for TGTextViewStream when it works, maybe someone else would like something like it.
As a work around (if you really need to use the basic_ostream rather than a one of derived class) use #ifdef __MAKECINT__
class TGTextViewStreamBuf
#else
class TGTextViewStreamBuf : public TGTextView,
public std::basic_streambuf<char,
std::char_traits<char> >
#endif
It is now implemented in 5-34-00-patches and soon in the master. Could you send me your full info (name, email) in order to add your contribution in the CREDITS file? Thanks a lot for you contribution! (and sorry for the loooong delay )
Good luck!
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