sd_bus_can

Name

sd_bus_can_send — Check which types can be sent over a bus object

Synopsis

#include <systemd/sd-bus.h>

`int sd_bus_can_send(`	sd_bus *`bus`,
	char `type)`;

Description¶

sd_bus_can_send() is mostly used for checking if file descriptor passing is available on the given bus. type can be any of the SD_BUS_TYPE constants.

Return Value¶

On failure, sd_bus_can_send() returns a negative errno-style error code. If values of the given type can be sent over the given bus, it returns a positive integer. Otherwise, it returns zero.

Errors¶

Returned errors may indicate the following problems:

-ENOPKG¶: The bus object bus could not be resolved.
-ENOTCONN¶: The input parameter bus is NULL or the bus is not connected.
-ECHILD¶: The bus object bus was created in a different process.

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.

All functions listed here are thread-agnostic and only a single thread may operate on a given object at any given time. Different threads may access the same object at different times. Multiple independent objects may be used from different threads in parallel.

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_bus_can_send() was added in version 221.