ERR41-CPP. Constructors of objects with static or thread storage duration must not throw exceptions

Not all exceptions can be caught, even with careful use of function try blocks. The C++ Standard, [except.handle], paragraph 13, states:

Exceptions thrown in destructors of objects with static storage duration or in constructors of namespacescope objects with static storage duration are not caught by a function-try-block on main() . Exceptions thrown in destructors of objects with thread storage duration or in constructors of namespace-scope objects with thread storage duration are not caught by a function-try-block on the initial function of the thread.

When declaring an object with static or thread storage duration, the type's constructor must be declared noexcept(true) and comply with ERR37-CPP. Honor exception specifications.

For more information on exception specifications of destructors, see DCL40-CPP. Destructors and deallocation functions must be declared noexcept.

Noncompliant Code Example

In this noncompliant example, the constructor of global may throw an exception during program startup (the std::string constructor accepting a const char * and a default allocator object is not marked noexcept(true) and thus allows all exceptions). This exception is not caught by the function-try-block on main(), resulting in a call to std::terminate() and abnormal program termination.

#include <string>
 
static const std::string global("...");

int main()
try {
  // ...
} catch(...) {
  // IMPORTANT: will not catch exceptions thrown
  // from the constructor of global.
}

Compliant Solution

Compliant code must prevent exceptions from escaping during program startup and termination. This compliant solution avoids defining a std::string at global namespace scope, and instead uses a static const char *:

static const char *global = "...";

int main() {
  // ...
}

Risk Assessment

Throwing an exception which cannot be caught results in abnormal program termination, and can lead to denial-of-service attacks.

Automated Detection

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

Related Guidelines

Bibliography