- sendfile(fdout, fdin, NULL, fdin_size);
+ ssize_t sent_size = sendfile(fdout, fdin, NULL, fdin_size);
+ xbt_assert(sent_size == fdin_size,
+ "Error while copying %s: only %zd bytes copied instead of %ld (errno: %d -- %s)",
+ target_executable.c_str(), sent_size, fdin_size, errno, strerror(errno));