Create a data server variable
#include <ds.h> int ds_create( ds_t dsdes, const char * variable_name, char flags, struct sigevent * sigevent );
All variables are global, so only one instance of the variable can exist in the data server process. The maximum length of a variable name is 60 characters.
If flags is 0, the variable is removed if you call ds_deregister(), or the process terminates.
libds
Use the -l ds option to qcc to link against this library.
The ds_create() function creates a variable, whose name is given by variable_name, on the data server identified by dsdes.
If the data referenced by variable_name changes, a proxy or signal, described in the sigevent structure, can be sent to the external application that created variable_name (see ds_set()).
We recommend the following event types for use with this function:
To display the current value of a variable on an HTML page, use the qnxvar token with the read tag. See the description of slinger in the Utilities Reference.
See slinger in the Utilities Reference.
Safety: | |
---|---|
Cancellation point | Yes |
Interrupt handler | No |
Signal handler | Yes |
Thread | Yes |
ds_flags(), ds_get(), ds_register(), ds_set(), sigevent