PACTYPE_LENGTH
pac->data.length = PACTYPE_LENGTH;
header_len = PACTYPE_LENGTH + (nbuffers * PAC_INFO_BUFFER_LENGTH);
header_len = PACTYPE_LENGTH + pac->nbuffers * PAC_INFO_BUFFER_LENGTH;
header_len = PACTYPE_LENGTH + (pac->nbuffers * PAC_INFO_BUFFER_LENGTH);
PACTYPE_LENGTH + (pac->nbuffers * PAC_INFO_BUFFER_LENGTH));