sd_bus_message_get_signature - Man Page

#include <systemd/sd-bus​.h>

const char* sd_bus_message_get_signature(sd_bus_message *message, int complete);

int sd_bus_message_is_empty(sd_bus_message *message);

int sd_bus_message_has_signature(sd_bus_message *message, const char *signature);

sd_bus_message_get_signature() returns the signature of message message​. If complete is true, the signature of the whole message is returned, and just the signature of the currently open container otherwise​.

sd_bus_message_is_empty() returns true if the message is empty, i​.e​. when its signature is empty​.

sd_bus_message_has_signature() returns true if the signature of the message message matches given signature​. Parameter signature may be NULL, this is treated the same as an empty string, which is equivalent to calling sd_bus_message_is_empty()​.

On success, sd_bus_message_get_signature() returns the signature, and NULL on error​.

The other functions return 0 or a positive integer on success​. On failure, they return a negative errno-style error code​.

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​.

sd_bus_message_get_signature(), sd_bus_message_is_empty(), and sd_bus_message_has_signature() were added in version 240​.

systemd(1), sd-bus(3), sd_bus_message_new(3)