Diagnostics library

Exception handling

The header <exception> provides several classes and functions related to exception handling in C++ programs.

Defined in header <exception>
exception	base class for exceptions thrown by the standard library components (class)
Capture and storage of exception objects
uncaught_exceptionuncaught_exceptions (removed in C++20*)(C++17)	checks if exception handling is currently in progress (function)
exception_ptr (C++11)	shared pointer type for handling exception objects (typedef)
make_exception_ptr (C++11)	creates an std::exception_ptr from an exception object (function template)
current_exception (C++11)	captures the current exception in a std::exception_ptr (function)
rethrow_exception (C++11)	throws the exception from an std::exception_ptr (function)
nested_exception (C++11)	a mixin type to capture and store current exceptions (class)
throw_with_nested (C++11)	throws its argument with std::nested_exception mixed in (function template)
rethrow_if_nested (C++11)	throws the exception from a std::nested_exception (function template)
Handling of failures in exception handling
Defined in header <exception>
terminate	function called when exception handling fails (function)
terminate_handler	the type of the function called by std::terminate (typedef)
get_terminate (C++11)	obtains the current terminate_handler (function)
set_terminate	changes the function to be called by std::terminate (function)
bad_exception	exception thrown when std::current_exception fails to copy the exception object (class)
Handling of exception specification violations (until C++17)
unexpected (deprecated in C++11)(removed in C++17)	function called when dynamic exception specification is violated (function)
unexpected_handler (deprecated in C++11)(removed in C++17)	the type of the function called by std::unexpected (typedef)
get_unexpected (deprecated in C++11)(removed in C++17)	obtains the current unexpected_handler (function)
set_unexpected (deprecated in C++11)(removed in C++17)	changes the function to be called by std::unexpected (function)

Exception categories

Several convenience classes are predefined in the header <stdexcept> to report particular error conditions. These classes can be divided into two categories: logic errors and runtime

Defined in header <stdexcept>
logic_error	exception class to indicate violations of logical preconditions or class invariants (class)
invalid_argument	exception class to report invalid arguments (class)
domain_error	exception class to report domain errors (class)
length_error	exception class to report attempts to exceed maximum allowed size (class)
out_of_range	exception class to report arguments outside of expected range (class)
runtime_error	exception class to indicate conditions only detectable at run time (class)
range_error	exception class to report range errors in internal computations (class)
overflow_error	exception class to report arithmetic overflows (class)
underflow_error	exception class to report arithmetic underflows (class)
tx_exception (TM TS)	exception class to cancel atomic transactions (class template)

Error numbers

Defined in header <cerrno>
errno	macro which expands to POSIX-compatible thread-local error number variable (macro variable)
E2BIG, EACCES, ..., EXDEV	macros for standard POSIX-compatible error conditions (macro constant)

System error (since C++11)

The header <system_error> defines types and functions used to report error conditions originating from the operating system, streams I/O, std::future

Defined in header <system_error>
error_category (C++11)	base class for error categories (class)
generic_category (C++11)	identifies the generic error category (function)
system_category (C++11)	identifies the operating system error category (function)
error_condition (C++11)	holds a portable error code (class)
errc (C++11)	the std::error_condition enumeration listing all standard <cerrno> macro constants (class)
error_code (C++11)	holds a platform-dependent error code (class)
system_error (C++11)	exception class used to report conditions that have an error_code (class)

Assertions

Assertions help to implement checking of preconditions in programs.

Defined in header <cassert>
assert	aborts the program if the user-specified condition is not true. May be disabled for release builds. (function macro)

Stacktrace (since C++23)

Defined in header <stacktrace>
stacktrace_entry (C++23)	representation of an evaluation in a stacktrace (class)
basic_stacktrace (C++23)	approximate representation of an invocation sequence consists of stacktrace entries (class template)

Debugging support (since C++26)

Defined in header <debugging>
breakpoint (C++26)	pauses the running program when called (function)
breakpoint_if_debugging (C++26)	calls std::breakpoint if std::is_debugger_present returns true (function)
is_debugger_present (C++26)	checks whether a program is running under the control of a debugger (function)

See also

static_assert declaration (C++11)	performs compile-time assertion checking
C documentation for Error handling