_S_C_F_e_e_d_e_r_G_e_t_F_l_a_g_s gets _f_l_a_g_s that describe a scanner's document feeding
capabilities. _s specifies a connection to a scanner driver obtained by a
call to _S_C_O_p_e_n(3), _S_C_O_p_e_n_F_i_l_e(3), or _S_C_O_p_e_n_S_c_r_e_e_n(3).
SSSSCCCCFFFFEEEEEEEEDDDDEEEERRRRFFFFLLLLAAAAGGGGSSSS and the values it can take on are defined in <_s_c_a_n_n_e_r._h> as
follows:
typedef unsigned int SCFEEDERFLAGS;
#define SC_HASFEEDER 1
#define SC_AUTOFEED 2
#define SC_PROGFEED 4
The meanings of the flags are as follows:
SSSSCCCC____HHHHAAAASSSSFFFFEEEEEEEEDDDDEEEERRRR: this flag is set if there is a document feeder attached to
the scanner.
SSSSCCCC____AAAAUUUUTTTTOOOOFFFFEEEEEEEEDDDD: this flag is set if the feeder can operate such that each
call to _S_C_S_c_a_n(3) causes the next document to be loaded.
SSSSCCCC____PPPPRRRROOOOGGGGFFFFEEEEEEEEDDDD: this flag is set if the feeder can operate such that
_S_C_S_c_a_n(3) can be called multiple times per document, with a call to
_S_C_F_e_e_d_e_r_A_d_v_a_n_c_e being necessary to load the next document.
_S_C_F_e_e_d_e_r_S_e_t_F_l_a_g_s should be called before calling _S_C_S_c_a_n(3) for scanners
for which _S_C_F_e_e_d_e_r_G_e_t_F_l_a_g_s yields both SSSSCCCC____AAAAUUUUTTTTOOOOFFFFEEEEEEEEDDDD and SSSSCCCC____PPPPRRRROOOOGGGGFFFFEEEEEEEEDDDD set.