sd_varlink_is_connected - Man Page
Query if a Varlink connection object is currently connected or idle
Synopsis
#include <systemd/sd-varlink.h>
int sd_varlink_is_connected(sd_varlink *link);
int sd_varlink_is_idle(sd_varlink *link);
Description
sd_varlink_is_connected() checks whether the specified Varlink connection object is currently connected or whether it has been fully disconnected already.
sd_varlink_is_idle() checks whether the specified Varlink connection object is currently connected but idle, i.e. may accept a method call for enqueuing (if client side of a Varlink connection) or is waiting for more incoming method calls to arrive (if server side of a Varlink connection).
Return Value
If the connection is currently connected sd_varlink_is_connected() returns a positive non-zero value. If disconnected it returns 0. If the connection currently is idle sd_varlink_is_idle() returns a positive non-zero integer. If not, returns 0. On failure, both functions return a negative errno error code.
Errors
Returned errors may indicate the following problems:
- -EINVAL
The specified Varlink connection is invalid.
Notes
Functions described here are available as a shared library, which can be compiled against and linked to with the libsystemd pkg-config(1) file.
The code described here uses getenv(3), which is declared to be not multi-thread-safe. This means that the code calling the functions described here must not call setenv(3) from a parallel thread. It is recommended to only do calls to setenv() from an early phase of the program when no other threads have been started.
History
sd_varlink_is_connected() was added in version 259.
sd_varlink_is_idle() was added in version 257.