NAME

       sd_bus_message_get_signature, sd_bus_message_is_empty, sd_bus_message_has_signature -
       Query bus message signature

SYNOPSIS

       #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);

DESCRIPTION

       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().

RETURN VALUE

       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.

   Errors
       Returned errors may indicate the following problems:

       -EINVAL
           The message parameter is NULL.

       NULL
           The message parameter is NULL.

NOTES

       These APIs are implemented as a shared library, which can be compiled and linked to with
       the libsystemd pkg-config(1) file.

SEE ALSO

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