sd_bus_set_fd(3) — Linux manual page


SD_BUS_SET_FD(3)              sd_bus_set_fd             SD_BUS_SET_FD(3)

NAME         top

       sd_bus_set_fd - Set the file descriptors to use for bus

SYNOPSIS         top

       #include <systemd/sd-bus.h>

       int sd_bus_set_fd(sd_bus *bus, int input_fd, int output_fd);

DESCRIPTION         top

       sd_bus_set_fd() sets the file descriptors used to communicate by
       a bus connection object. Both input_fd and output_fd must be
       valid file descriptors, referring to stream-based file objects
       (e.g. a stream socket, a pair of pipes or FIFOs, or even a TTY
       device).  input_fd must be readable, and output_fd must be
       writable. The same file descriptor may be used (and typically is
       used) as both the input and the output file descriptor. This
       function must be called before the bus connection is started via

       The bus connection object will take possession of the passed file
       descriptors and will close them automatically when it is freed.
       Use sd_bus_set_close_on_exit(3) to turn off this behaviour.

RETURN VALUE         top

       On success, sd_bus_set_fd() returns a non-negative integer. On
       failure, it returns a negative errno-style error code.

       Returned errors may indicate the following problems:

           An invalid bus object was passed.

           Added in version 248.

           The bus connection was allocated in a parent process and is
           being reused in a child process after fork().

           Added in version 248.

           An invalid file descriptor was passed to sd_bus_set_fd().

           Added in version 248.

           The bus cannot be resolved.

           Added in version 248.

           The bus connection has already been started.

           Added in version 248.

NOTES         top

       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

HISTORY         top

       sd_bus_set_fd() was added in version 248.

SEE ALSO         top

       systemd(1), sd-bus(3), sd_bus_get_fd(3), sd_bus_start(3)

COLOPHON         top

       This page is part of the systemd (systemd system and service
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       This page was obtained from the project's upstream Git repository
       ⟨⟩ on 2023-12-22.  (At that
       time, the date of the most recent commit that was found in the
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       (which is not part of the original manual page), send a mail to

systemd 255                                             SD_BUS_SET_FD(3)

Pages that refer to this page: sd_bus_get_fd(3)sd_bus_start(3)systemd.directives(7)systemd.index(7)