#include <systemd/sd-bus.h>
sd_bus_set_method_call_timeout()
sd_bus_get_method_call_timeout() queries the default D-Bus method call timeout of bus. If no method call timeout was set using sd_bus_set_method_call_timeout(), the timeout is read from the $SYSTEMD_BUS_TIMEOUT environment variable. If this environment variable is unset or does not contain a valid timeout, the implementation falls back to a predefined method call timeout of 25 seconds. Note that $SYSTEMD_BUS_TIMEOUT is read once and cached so callers should not rely on being able to change the default method call timeout at runtime by changing the value of $SYSTEMD_BUS_TIMEOUT. Instead, call sd_bus_set_method_call_timeout() to change the default method call timeout.
On success, these functions return a non-negative integer. On failure, they return a negative errno-style error code.
Returned errors may indicate the following problems:
-EINVAL
-ENOPKG
These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.
systemd(1), sd-bus(3), sd_bus_call(3)