.TH sc_read_binary 3 "April 2003" "OpenSC Programmer's Manual
.SH NAME
sc_read_binary, sc_write_binary, sc_update_binary \- read and write files on a smart card
.SH SYNOPSIS
.nf
.B #include <opensc.h>
.sp
.BI "int sc_read_binary(sc_card_t *" card ",
.BI "                   unsigned int " offset ",
.BI "                   unsigned char *" buffer ",
.BI "                   size_t " count ",
.BI "                   unsigned long " flags ");
.BI "int sc_write_binary(sc_card_t *" card ",
.BI "                   unsigned int " offset ",
.BI "                   const unsigned char *" buffer ",
.BI "                   size_t " count ",
.BI "                   unsigned long " flags ");
.BI "int sc_update_binary(sc_card_t *" card ",
.BI "                   unsigned int " offset ",
.BI "                   const unsigned char *" buffer ",
.BI "                   size_t " count ",
.BI "                   unsigned long " flags ");
.fi
.SH DESCRIPTION
These functions read and write transparent elementary files (EFs)
on a smart card. The correspond to the ISO 7816 functions
READ BINARY, WRITE BINARY and UPDATE BINARY, respectively.
(The difference between write and update is that the former
means writing to an uninitialized file, while the latter
is intended to update a file region previously written to -
some card have different access conditions for these operations).
.PP
The \fIoffset\fP argument specifies the file offset in bytes.
Note that some cards may not allow writing at arbitrary offsets.
Some versions of the GPK require that read/write operations on
transparent files are aligned on a 4-byte boundary.
.PP
The \fIflags\fP argument is currently not used, and should be set
to 0.
.SH RETURN VALUE
If an error occurred, a negative error code is returned, as described
in \fbsc_error\fP(3). Otherwise, the function will return the
number of bytes read or written.
.SH SEE ALSO
.BR sc_file (3),
.BR sc_path (3),
.BR sc_establish_context (3),
.BR sc_select_file (3),
.BR sc_read_record (3),
.BR sc_delete_file (3),
.BR sc_create_file (3),
.BR sc_file_free (3).
.SH AUTHOR
This manual page was written by Olaf Kirch <okir@suse.de>