Some of these limitations with possible workarounds are discussed
in detail elsewhere in this document. Please be aware that some
of these limitations are platform-specific.
For a complete list of known limitations, search for the keyword
"limitations" in the HP C++ Online
Programmer's Guide.
Trigger Floating Point exceptions
before using library routines |
 |
Programs that use floating point arithmetic need to trigger
Floating Point exceptions before entering a library routine. For
example a Floating Point divide should be followed by a Floating
Point store, otherwise, code within the library may trigger the
floating point exception, interrupting the library code rather than
your code.
The reason for this behavior is that in this release, the
Unwind component of libcl.a and libcl.sl
uses floating point operations in more places than earlier versions
of the library. Programs that do not trigger Floating Point exceptions
before entering Unwind library routines may have the exception triggered
from with the Unwind routine.
The setjmp/longjmp and +eh option |
|
Code compiled in compiler mode with the +eh option should
not use setjmp/longjmp. To use setjump/longjmp with +eh in translator
mode, replace all setjmp/longjmp calls with Setjmp/Longjmp. You
must also must change the #include
from <setjmp.h> to <Setjmp.h>.
Kernel threads unsupported |
|
The thread-safe level of the code generated by HP C++ depends
on which libC routines are called with the possible exception of
static constructors for function scope statics or +eh co
de.
Thread-safe levels depends on which particular interface and
the type of threads.
Table 4-1 Thread-safe
Levels
| | Kernel Threads | User Threads |
|---|
Generated Code: |
Function-scope statics | Thread-Restricted C. User owns local
variable. | Thread-Restricted C. User owns the local
variable. |
File-scope static and globals | Thread-Restricted C for dynamic loading
of shared libraries. Ordering of initialization may be
more
of a problem. | Thread-Restricted C for dynamic loading
of shared libraries. Ordering of initialization may be
more
of a problem. |
+eh code | Thread-Restricted A. Thread-Unusable
unless other threads are just C. | Thread-Safe Performance
Constrained. |
libC
interfaces: |
+eh ([re]throw) | Thread-Restricted A. Thread-Restricted
B if only one thread is written in C++. | Thread-Safe Performance
Constrained. |
I/O (iostreams,
strstream, etc.) | Thread-Restricted C. | Thread-Safe Performance Constrained.
Tuned if using predefined streams: cin, cout,
cerr, clog. Otherwise Thread-Restricted
C. |
vec new/delete | Thread-Restricted C. | Thread-Safe
Performance Constrained. |
cxxshl_load
and cxxshl_unload | Thread-Restricted C. | Thread-Restricted C. |
Others | Probably references no statics/globals
so completely safe. libC is not
fork-safe. It assumes no cancellations are possible. | Probably references no statics/globals
so completely safe. libC is not fork-safe.
It assumes no
cancellations are possible. |
