sd_bus_message_get_type - Man Page

#include <systemd/sd-bus​.h>

int sd_bus_message_get_type(sd_bus_message *m, uint8_t *type);

sd_bus_error* sd_bus_message_get_error(sd_bus_message *m);

int sd_bus_message_get_errno(sd_bus_message *m);

sd_bus_creds* sd_bus_message_get_creds(sd_bus_message *m);

int sd_bus_message_is_signal(sd_bus_message *m, const char *interface, const char *member);

int sd_bus_message_is_method_call(sd_bus_message *m, const char *interface, const char *member);

int sd_bus_message_is_method_error(sd_bus_message *m, const char *name);

sd_bus_message_get_type() returns the type of a message in the output parameter type, one of SD_BUS_MESSAGE_METHOD_CALL, SD_BUS_MESSAGE_METHOD_RETURN, SD_BUS_MESSAGE_METHOD_ERROR, SD_BUS_MESSAGE_SIGNAL​. This type is either specified as a parameter when the message is created using sd_bus_message_new(3), or is set automatically when the message is created using sd_bus_message_new_signal(3), sd_bus_message_new_method_call(3), sd_bus_message_new_method_error(3) and similar functions​.

sd_bus_message_get_error() returns the error stored in the message m, if there is any​. Otherwise, it returns NULL​. sd_bus_message_get_errno() returns the error stored in the message m as a positive errno-style value, if there is any​. Otherwise, it returns zero​. Errors are mapped to errno values according to the default and any additional registered error mappings​. See sd-bus-errors(3) and sd_bus_error_add_map(3)​.

sd_bus_message_get_creds() returns the message credentials attached to the message m​. If no credentials are attached to the message, it returns NULL​. Ownership of the credentials instance is not transferred to the caller and hence should not be freed​.

sd_bus_message_is_signal() checks if message m is a signal message​. If interface is non-null, it also checks if the message has the same interface set​. If member is non-null, it also checks if the message has the same member set​. Also see sd_bus_message_new_signal(3)​. It returns true when all checks pass​.

sd_bus_message_is_method_call() checks if message m is a method call message​. If interface is non-null, it also checks if the message has the same interface set​. If member is non-null, it also checks if the message has the same member set​. Also see sd_bus_message_new_method_call(3)​. It returns true when all checks pass​.

sd_bus_message_is_method_error() checks if message m is an error reply message​. If name is non-null, it also checks if the message has the same error identifier set​. Also see sd_bus_message_new_method_error(3)​. It returns true when all checks pass​.

On success, these functions (except sd_bus_message_get_error() and sd_bus_message_get_creds()) return a non-negative integer​. On failure, they return a negative errno-style error code​. sd_bus_message_get_errno() always returns a non-negative integer, even on failure​.

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_type(), sd_bus_message_is_signal(), sd_bus_message_is_method_call(), and sd_bus_message_is_method_error() were added in version 240​.

sd_bus_message_get_error(), sd_bus_message_get_errno(), and sd_bus_message_get_creds() were added in version 246​.

systemd(1), sd-bus(3), sd_bus_message_new(3), sd_bus_message_set_destination(3), sd-bus-errors(3), sd_bus_error_add_map(3)

sd-bus(3), sd_bus_call(3), sd_bus_creds_get_pid(3), sd_bus_creds_new_from_pid(3), sd_bus_negotiate_fds(3), systemd.directives(7), systemd.index(7).

The man pages sd_bus_message_get_creds(3), sd_bus_message_get_errno(3), sd_bus_message_get_error(3), sd_bus_message_is_method_call(3), sd_bus_message_is_method_error(3) and sd_bus_message_is_signal(3) are aliases of sd_bus_message_get_type(3).