while ((t = xbt_fifo_pop(h_simdata->mbox[channel])) == NULL) {
xbt_assert2(!(h_simdata->sleeping[channel]),
"A process (%s(%d)) is already blocked on this channel",
while ((t = xbt_fifo_pop(h_simdata->mbox[channel])) == NULL) {
xbt_assert2(!(h_simdata->sleeping[channel]),
"A process (%s(%d)) is already blocked on this channel",