What is the difference between libstdc++ and STLport c++

[Franklin]

Hello: 

I have a linbrary named as PWLib which has been suceessfully compiled using
gcc. But when I using a cross compiler on arm7tdmi+uclinux, there are many
warnings such as the following:
 /home/stone/pwlib/include/ptlib/object.h: In function `class _STL:ostream 
& operator <<(_STL:ostream &, const PFloat80l &)': 
/home/stone/pwlib/include/ptlib/object.h:2604: ambiguous overload for 
`_STL::basic_ostream<char,_STL::char_traits<char> > & << const long double &


/usr/local/arm-elf/stlport/stl/_ostream.h6: candidates are: class 
_STL::basic_ostream<char,_STL::char_traits<char> > & 
_STL::basic_ostream<char,_STL::char_traits<char> >:operator <<(unsigned 
char) 
/usr/local/arm-elf/stlport/stl/_ostream.h8: class 
_STL::basic_ostream<char,_STL::char_traits<char> > & 
_STL::basic_ostream<char,_STL::char_traits<char> >:operator <<(short int) 
Someone told me that is becuase the gcc using libstdc++ while the cross
compiler STLport C++. So would you please tell me what is the difference
between libstdc++ and STLportC++. How can I change the pwlib codes so that
it can cooperate with STLport C++. 

Thank you very much in advanced. 

Bestwishes
Franklin 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20030520/2448a7ed/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: IMSTP.gif
Type: unknown/unknown
Size: 494 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20030520/2448a7ed/attachment.bin>