Tews Technologies TPMC118-SW-95, Руководство пользователя

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TPMC118-SW-95 – QNX6 Neutrino Device Driver Page 9 of 30
3.3 devctl()
NAME
devctl() – device control functions
SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
#include <devctl.h>
int devctl
(
int
filedes,
int dcmd,
void *data_ptr,
size_t n_bytes,
int *dev_info_ptr
)
DESCRIPTION
The devctl function sends a control code directly to a device, specified by filedes , causing the
corresponding device to perform the requested operation.
The argument dcmd specifies the control code for the operation.
The arguments data_ptr and n_bytes depends on the command and will be described for each
command in detail later in this chapter. Usually data_ptr points to a buffer that passes data between
the user task and the driver and n_bytes defines the size of this buffer.
The argument dev_info_ptr is unused for the TPMC118 driver and should be set to NULL.