sd_bus_message_get_type(3) — Linux manual page

SD_BUS_M..._GET_TYPE(3)  sd_bus_message_get_type SD_BUS_M..._GET_TYPE(3)

NAME

       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

       #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

       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

       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

       Functions described here are available as a shared library, which
       can be compiled against and linked to with the
       libsystemd pkg-config(1) file.

       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.

HISTORY

       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.

SEE ALSO

       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

       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 2024-06-14.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2024-06-13.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

systemd 257~devel                                SD_BUS_M..._GET_TYPE(3)

Pages that refer to this page: 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)

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