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15.6 Non-returning Functions

A "non-returning" function is a function which cannot return normally. It can transfer control only through longjmp(), throw (in C++), or similar mechanisms. The most prominent function of this class is the abort function. Non-returning functions are declared with a void return type.

It helps the compiler’s ability to emit sensible warnings, following data-flow analysis, to declare which functions are non-returning.

To decorate function declarations and function definitions, you can use the _Noreturn keyword. No modules are needed, as Gnulib arranges for <config.h> to define _Noreturn to an appropriate replacement on platforms lacking it.

Gnulib has two modules that support such a declaration:

Which of the two modules to use? If the non-returning functions you have to declare are unlikely to be accessed through function pointers, you should use module stdnoreturn; otherwise the module noreturn provides for better data-flow analysis and thus for better warnings.

For a detailed description of the stdnoreturn module, see stdnoreturn.h.


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