Thank you for reporting the issue.

The XED library uses the __attribute__((noreturn)) directive to mark functions that do not return, instead of the _Noreturn keyword. This decision was made to maintain backward compatibility with C99 standards (before C11) where _Noreturn is not supported.

When you include <stdnoreturn.h> (a C11 header) before the XED library, GCC encounters a potential conflict between the _Noreturn keyword (introduced in C11) and the __attribute__((noreturn)) attribute used in XED. Both serve the same purpose, but GCC may issue warnings when it detects both attributes in the same code, sometimes ignoring one.

To resolve this issue, I recommend swapping the order in which you include headers. By including the XED library headers before including <stdnoreturn.h>, you ensure that GCC correctly handles the __attribute__((noreturn)) directive used by the XED library, while still allowing you to use the _Noreturn keyword in your own code if needed.

You can adjust it to:

#include <xed/xed-interface.h>
#include <stdnoreturn.h>

Please let us know if this solution works for you.

Thank you for the comprehensive response. Swapping the order of #includes does work in this simple example, however in our full codebase we include external C11 headers that do or may in the future include stdnoreturn.h themselves. Combined with #include sorting it is generally difficult for us to ensure Xed headers are always #included before stdnoreturn.h.

Please fix the headers to work in a C11 codebase. For C99 compatibility you can use the __attribute__((__noreturn__)) alias, but I recommend using the standardized noreturn or [[noreturn]] attributes when compiling in C11 or C23 mode respectively.

A fix will be available with the upcoming external release.