The entries below are for historical interest only or possibly for people using really old versions of UW7 or OSR5.
jls@sco.com

The UDK C++ compiler does not yet contain a full implementation of
the draft ANSI/ISO C++ Standard library.  In addition to the
Standard Template Library (STL), which is covered by a separate
FAQ entry, the new standard library includes:

   * language support and diagnostic classes
   * new, templatized versions of the iostreams and complex classes that
     were in the old de facto AT&T standard library
   * a number of new facilities, such as strings, locales, and valarrays
     (for Fortran-wannabe numeric computation).

The current SCO UDK C++ fully implements the language support and diagnostic
classes (clauses 18 and 19 of the draft standard).

The current SCO UDK C++ does not implement the new standard versions of the
iostreams and complex classes, but rather still contains the old
non-templatized versions, slightly updated for new types such as bool.

The current SCO UDK C++ does not implement any of the new facilities.

Three commercial STL vendors -- Modena, Rogue Wave, and Dinkumware -- also
market full standard library implementations, but on an OEM or large site
basis, that is generally not available for SCO platforms.

There are free implementations of the following parts of the library.
(If these links get out of date, try consulting the comp.std.c++ FAQ at
http://reality.sgi.com/employees/austern_mti/std-c++/faq.html#C6
for where to get them from.)

string

A partial implementation of the string class is available that Modena wrote;
it is at http://aw.com/cp/musser-saini-source.html .

The file bstring.h in it needs one change to compile under UDK C++: change
the #ifndef __BOOL_DEFINED on line 36 to

     #ifndef _BOOL

The ObjectSpace free STL distribution also includes a string implementation,
but building it has the same problems as building their STL (see above).

valarray

A partial implementation of valarray is available that Daveed Vandevoorde
wrote; it is at ftp://ftp.cs.rpi.edu/pub/vandevod/Valarray . The Rel2_0Beta2
version there needs one change to compile with the UDK C++ compiler: add the
lines

     #ifdef __USLC__         /* SCO UDK C++ */
     #   define COMPILER_RECOGNIZED
     #endif

at line 43 of file valplat.h.