sc_establish_context.3

读写Smart卡加解密接口的程序

.TH sc_establish_context 3 "April 2003" "OpenSC Programmer's Manual
.SH NAME
sc_establish_context \- establish OpenSC context
.SH SYNOPSIS
.nf
.B #include <opensc.h>
.sp
.BI "int sc_establish_context(sc_context_t **" ctx ",
.BI "                         const char *" app_name ");
.fi
.SH DESCRIPTION
This function establishes an OpenSC context. This context is required
in all subsequent calls to OpenSC functions.
.PP
\fIctx\fP is a pointer to a pointer that will receive the allocated context.
.PP
\fIapp_name\fP is a string that identifies the application. This string will
be used to apply application-specific from the \fBopensc.conf\fP(5) configuration
file.  If \fBNULL\fP is passed, just the settings specified in the \fBdefault\fP
section apply; otherwise, settings from the section identified by \fIapp_name\fP
will be applied as well.
.PP
The \fBsc_context\fP structure contains the following members, among
others:
.PP
.in +4
.nf
.B "typedef struct sc_context {
.B "     struct sc_reader *reader[SC_MAX_READERS];
.B "     int reader_count;
.B "} sc_context_t;
.fi
.in
.PP
The \fBreader_count\fP field contains the number of readers found by
OpenSC. Information on the individual card readers are stored in
\fBsc_reader\fP objects, which look like follows:
.PP
.in +4
.nf
.B "typedef struct sc_reader {
.B "     char *name;
.B "     int slot_count;
.B "} sc_reader_t;
.fi
.in
.PP
Here, \fBname\fP contains a printable name of the reader, and \fBslot_count\fP
shows the number of slots supported by this device.
.PP
Of course, these structs contain other members as well, but applications
usually should not use these fields.
.SH RETURN VALUE
If a context could be established, 0 is returned. Otherwise, a negative
error code is returned, as described in \fbsc_error\fP(3).
.SH SEE ALSO
.BR sc_release_context (3),
.BR sc_detect_card_presence (3),
.BR sc_connect_card (3).
.SH AUTHOR
This manual page was written by Olaf Kirch <[e-mail]>