sd_bus_message_is_signal(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | COLOPHON

SD_BUS_MESSAGE_GET_TYPE(3) sd_bus_message_get_typeSD_BUS_MESSAGE_GET_TYPE(3)

NAME         top

       sd_bus_message_get_type, sd_bus_message_get_error,
       sd_bus_message_get_errno, sd_bus_message_get_creds,
       sd_bus_message_is_signal, sd_bus_message_is_method_call,
       sd_bus_message_is_method_error - Query bus message
       addressing/credentials metadata

SYNOPSIS         top

       #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);

DESCRIPTION         top

       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.

RETURN VALUE         top

       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.

   Errors
       Returned errors may indicate the following problems:

       -EINVAL
           The message parameter m or an output parameter is NULL.

NOTES         top

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

SEE ALSO         top

       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)

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have a bug
       report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2020-09-18.  (At that
       time, the date of the most recent commit that was found in the repos‐
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       of the original manual page), send a mail to man-pages@man7.org

systemd 246                                       SD_BUS_MESSAGE_GET_TYPE(3)

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