Diffrerent output of the same program on HP aCC and Linux (Intel/g++) for std::stringstream

[AlexVi2]

Hi,

While migratining from deprecated std::strstream to std::stringstream we are faced with some problem related to std::stringstream.

The same program produces different output on HP aCC and on Intel/g++ compilers on Linux.

Here is some fragment of different outputs.

HP aCC

Compilation:

> aCC aaa21.cpp

> aCC +DD64 aaa21.cpp

[ Line-135, doStringStream] stream.str() = <xyz>

[ Line-136, doStringStream] stream.str().c_str() = <xyz>

[ Line-137, doStringStream] stream.str().data() = <xyz>

[ Line-139, doStringStream] stream.tellp() = <3>

[ Line-140, doStringStream] stream.str().size() = <3>

[ Line-141, doStringStream] stream.rdbuf()->str().size() = <3>

[ Line-142, doStringStream] stream.rdbuf()->in_avail() = <3>

Linux Intel/g++ compilers

> icpc  aaa21.cpp

> g++  aaa21.cpp

[ Line-135, doStringStream] stream.str() = <xyzdefQQQQQQQQQQQQQQQQQQQ>

[ Line-136, doStringStream] stream.str().c_str() = <xyzdefQQQQQQQQQQQQQQQQQQQ>

[ Line-137, doStringStream] stream.str().data() = <xyzdefQQQQQQQQQQQQQQQQQQQ>

[ Line-139, doStringStream] stream.tellp() = <3>

[ Line-140, doStringStream] stream.str().size() = <25>

[ Line-141, doStringStream] stream.rdbuf()->str().size() = <25>

[ Line-142, doStringStream] stream.rdbuf()->in_avail() = <25>

The program and logs attached.

Any suggestions?

Thanks.

Alex

[Dennis Handly · Accepted solution]

The 98 C++ Standard 27.7.1.3(16) says basic_stringbuf::setbuf is implementation defined.

As documented in  basic_stringbuf(3C++), RW's basic_stringbuf::setbuf copies the current contents (empty) into the new buffer and uses the current pointer relative offsets.

(Contrary to the documentation, the buffer isn't owned, if not NULL.)

You may try this workaround:

#ifdef WORK
                std::string str_tmp(pStringStream, i_size);
                std::stringstream stream(str_tmp);
#else
                std::stringstream stream;
                stream.rdbuf()->pubsetbuf(pStringStream, i_size);
#endif

[AlexVi2]

Dennis, thank you.

[Dennis Handly]

>thank you.

If you're happy please also assign kudos.