C23 did not get around to introducing this kind of forward declaration (and, although GCC has had them for a long time, Clang has not implemented that extension

C23 did not get around to introducing this kind of forward declaration (and, although GCC has had them for a long time, Clang has not implemented that extension either). I think I remember Gustedt (the chair for C11 and C17) openly advocating against the ages-old practice[1] of putting lengths after pointers, I suspect in part because of this problem, and Meneide (the current one) also puts lengths first in his proposed encoding APIs. In any case, the proposal[2] (ETA: by Martin Uecker, who’s also spoken up both in the linked thread and here) is still under consideration, it just didn’t get into C23. [1] With main() being the exception. [2] Latest version being https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3121.pdf https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3121.pdf.