Check for a library with C++ code

[Sebastian Huber]

Hello,
how can I write a check for a library which contain only functions and classes 
in a namespace?
The easiest function is 'std::string TACO::errorString( long e)'.

I tried this:

AC_CHECK_LIB(TACOExtensions,errorString,found=yes,found=no,)

but it resulted in:

/home/huber/taco/frmII/tacodevel/build/client/io/configure:2971: undefined 
reference to `errorString'

and

AC_CHECK_LIB(TACOExtensions,TACO::errorString,found=yes,found=no,)

resulted in a syntax error because the TACO namespace was not declared. The 
output of nm looks like:

$nm /usr/local/dshome2/lib/linux/x86/libTACOExtensions.a | grep errorString
00000870 t _GLOBAL_.D.errorString__4TACOl
00000850 t _GLOBAL_.I.errorString__4TACOl
00000000 T errorString__4TACOl

Thank you for help in advance.

        Sebastian