systemd sd_bus_call 3 sd_bus_call sd_bus_call_async Invoke a D-Bus method call #include <systemd/sd-bus.h> int sd_bus_call sd_bus *bus sd_bus_message *m uint64_t usec sd_bus_error *ret_error sd_bus_message **reply int sd_bus_call_async sd_bus *bus sd_bus_slot **slot sd_bus_message *m sd_bus_message_handler_t callback void *userdata uint64_t usec sd_bus_call() takes a complete bus message object and calls the corresponding D-Bus method. The response is stored in reply. usec indicates the timeout in microseconds. If ret_error is not NULL and sd_bus_call() returns an error, ret_error is initialized to an instance of sd_bus_error describing the error. sd_bus_call_async() is like sd_bus_call() but works asynchronously. The callback shall reference a function to call when the event source is triggered. The userdata pointer will be passed to the callback function, and may be chosen freely by the caller. If slot is not NULL and sd_bus_call_async() succeeds, slot is set to a slot object which can be used to cancel the method call at a later time using sd_bus_slot_unref3. If slot is NULL, the lifetime of the method call is bound to the lifetime of the bus object itself, and it cannot be cancelled independently. See sd_bus_slot_set_floating3 for details. The callback function is called when the response arrives and receives the response, userdata and a sd_bus_error object as its arguments. The sd_bus_error object is unused here and should be ignored. If callback returns a non-negative integer when called, a debug message is logged along with details about the response. To determine whether the method call succeeded, use sd_bus_message_is_method_error3 on the reply object returned by sd_bus_call() or passed to the callback of sd_bus_call_async(). If usec is zero, the timeout set using sd_bus_set_method_call_timeout3 is used. If no method call timeout was set, 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 The input parameter m is NULL. The input parameter m is not a D-Bus method call. To create a new D-Bus method call, use sd_bus_message_new_method_call3. The input parameter m has the BUS_MESSAGE_NO_REPLY_EXPECTED flag set. The input parameter error is non-NULL but was not set to SD_BUS_ERROR_NULL. -ECHILD The bus connection was allocated in a parent process and is being reused in a child process after fork(). -ENOTCONN The bus parameter bus is NULL or the bus is not connected. -ECONNRESET The client was disconnected while waiting for the response. -ETIMEDOUT A response was not received within the given timeout. -ELOOP The message m is addressed to its own client. -ENOMEM Memory allocation failed. systemd1, sd-bus3, sd_bus_call_method3, sd_bus_call_method_async3, sd_bus_message_new_method_call3, sd_bus_message_append3