egd_get_cap - Query various information about the device
capabilities
#include <eegdev.h>
int egd_get_cap(const struct eegdev* dev, int
cap, void* val);
egd_get_cap() returns the information about the capability
specified by cap of the recording device referenced by dev by
the mean of the pointer val.
The type of pointer passed through val is dependent on the
requested capability cap which can be one the following (The expected
type pointed by val is provided in parenthesis):
- EGD_CAP_FS
(int)
- Sampling frequency that is currently set. The same value is returned by
the function.
- EGD_CAP_TYPELIST
(const int*)
- Array of sensor types sampled by the device terminated by -1. These values
became valid as argument for egd_sensor_name(3) when opening the
device dev if they were not yet before. The number of elements in
the array (excluding the -1 element) is provided by the return value of
the function.
- EGD_CAP_DEVTYPE
(const char*)
- Null terminated string describing the type of the recording device
(Manufacturer and model if dev refers to actual hardware). The
length of string (excluding the null character) is provided by the return
value of the function.
- EGD_DEVID
(const char*)
- Null-terminated string describing the model of the recording device (or an
unique identifier of the resource). The length of string (excluding the
null character) is provided by the return value of the function.
In case of success, the function returns a positive value
depending on the requested capability. Otherwise, -1 is returned and
errno is set accordingly.
egd_get_cap() will fail if:
- EINVAL
- dev is NULL, cap is not valid value or val is NULL
while cap is not EGD_CAP_FS.