sc_detect_card_presence.3

读写Smart卡加解密接口的程序

.TH sc_detect_card_presence 3 "April 2003" "OpenSC Programmer's Manual
.SH NAME
sc_detect_card_presence \- detect whether a card is present in a reader
.SH SYNOPSIS
.nf
.B #include <opensc.h>
.sp
.BI "int sc_detect_card_presence(sc_reader_t *" reader ",
.BI "                            int " slot ");
.fi
.SH DESCRIPTION
This function is used to detect the presence of a smart card in
a card reader device. The \fIslot\fP parameter identifies the
card reader's slot. Slots are numbered consecutively, starting at
\fB0\fP.
.SH RETURN VALUE
If a card is present, a positive value is returned that is a combination
of the following flags:
.TP
.B SC_SLOT_CARD_PRESENT
A card was detected.
.TP
.B SC_SLOT_CARD_CHANGED
The card was inserted and/or removed since the last call. Note that
this flag is not entirely reliable depending on the OS platform and
middleware. CTAPI doesn't support it at all, for instance, while PCSC
on Windows occasionally returns false CHANGE events.
.PP
If an error occurred, a negative error code is returned, as described
in \fbsc_error\fP(3).
.SH SEE ALSO
.BR sc_establish_context (3),
.BR sc_wait_for_event (3),
.BR sc_connect_card (3).
.SH AUTHOR
This manual page was written by Olaf Kirch <[e-mail]>