Retrieve a data server variable
Synopsis:
#include <ds.h>
int ds_get( ds_t dsdes,
const char* variable_name,
const char* variable_data,
size_t data_len );
Arguments:
- dsdes
- A data server descriptor returned by
ds_register().
- variable_name
- The name of the data server variable that you want to get.
- variable_data
- A buffer where the function can store the data associated with the
variable.
- data_len
- The size of the buffer, in bytes.
Library:
libds
Use the -l ds option to
qcc
to link against this library.
Description:
The ds_get() function retrieves the data corresponding to
variable_name from the data server dsdes,
and places it in the buffer pointed to by
variable_data.
Returns:
The amount of data written to the buffer variable_data,
or -1 if an error occurs (errno is set).
Errors:
- EBADF
- Invalid file descriptor dsdes.
- EMSGSIZE
- The buffer isn't big enough for the data.
- ESRCH
- The variable doesn't exist in the data server.
Classification:
QNX Neutrino
Safety: |
|
Cancellation point |
Yes |
Interrupt handler |
No |
Signal handler |
Yes |
Thread |
Yes |