sd_bus_message_get_signature(3) — Linux manual page

SD_BUS_...GNATURE(3)  sd_bus_message_get_signature  SD_BUS_...GNATURE(3)

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

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

SEE ALSO

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

COLOPHON

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       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
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       (which is not part of the original manual page), send a mail to
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systemd 257~devel                                   SD_BUS_...GNATURE(3)

Pages that refer to this page: sd-bus(3), systemd.directives(7), systemd.index(7)

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