Neither Fortran standard nor gfortran support calling vararg C function from Fortran. It used to work 'by chance' for most Debian supported architectures, but was broken for POWER by GCC PR fortran/87689 [1]. This GCC PR request [2] explains it all. . [1] https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=268992 [2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92361 ===================================================================
