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

SD_BUS_MESSAGE_APPEND_BASIC(3)s_message_append_basic_MESSAGE_APPEND_BASIC(3)

NAME         top

       sd_bus_message_append_basic - Attach a single field to a message

SYNOPSIS         top

       #include <systemd/sd-bus.h>

       int sd_bus_message_append_basic(sd_bus_message *m, char type,
                                       const void *p);

DESCRIPTION         top

       sd_bus_message_append_basic() appends a single field to the message
       m. The parameter type determines how the pointer p is interpreted.
       type must be one of the basic types as defined by the Basic Types[1]
       section of the D-Bus specification, and listed in the table below.

       Table 1. Item type specifiers
       ┌──────────┬─────────────────────────┬────────────────┬──────────┬────────────┐
       │Specifier Constant                Description    Size     Expected C │
       │          │                         │                │          │ Type       │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"y"       │ SD_BUS_TYPE_BYTE        │ unsigned       │ 1 byte   │ uint8_t    │
       │          │                         │ integer        │          │            │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"b"       │ SD_BUS_TYPE_BOOLEAN     │ boolean        │ 4 bytes  │ int        │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"n"       │ SD_BUS_TYPE_INT16       │ signed         │ 2 bytes  │ int16_t    │
       │          │                         │ integer        │          │            │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"q"       │ SD_BUS_TYPE_UINT16      │ unsigned       │ 2 bytes  │ uint16_t   │
       │          │                         │ integer        │          │            │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"i"       │ SD_BUS_TYPE_INT32       │ signed         │ 4 bytes  │ int32_t    │
       │          │                         │ integer        │          │            │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"u"       │ SD_BUS_TYPE_UINT32      │ unsigned       │ 4 bytes  │ uint32_t   │
       │          │                         │ integer        │          │            │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"x"       │ SD_BUS_TYPE_INT64       │ signed         │ 8 bytes  │ int64_t    │
       │          │                         │ integer        │          │            │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"t"       │ SD_BUS_TYPE_UINT64      │ unsigned       │ 8 bytes  │ uint64_t   │
       │          │                         │ integer        │          │            │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"d"       │ SD_BUS_TYPE_DOUBLE      │ floating-point │ 8 bytes  │ double     │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"s"       │ SD_BUS_TYPE_STRING      │ Unicode string │ variable │ char[]     │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"o"       │ SD_BUS_TYPE_OBJECT_PATH │ object path    │ variable │ char[]     │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"g"       │ SD_BUS_TYPE_SIGNATURE   │ signature      │ variable │ char[]     │
       ├──────────┼─────────────────────────┼────────────────┼──────────┼────────────┤
       │"h"       │ SD_BUS_TYPE_UNIX_FD     │ UNIX file      │ 4 bytes  │ int        │
       │          │                         │ descriptor     │          │            │
       └──────────┴─────────────────────────┴────────────────┴──────────┴────────────┘

       The value of the parameter is copied into a memory area held by the
       message object, stays in the possession of the caller and may hence
       be freely changed after this call without affecting the bus message
       it has been added to. If type is "h" (UNIX file descriptor), the
       descriptor is duplicated by this call and the passed descriptor stays
       in possession of the caller.

       For types "s", "o", and "g", the parameter p is interpreted as a
       pointer to a NUL-terminated character sequence. As a special case, a
       NULL pointer is interpreted as an empty string. The string should be
       valid Unicode string encoded as UTF-8. In case of the two latter
       types, the additional requirements for a D-Bus object path or type
       signature should be satisfied. Those requirements should be verified
       by the recipient of the message.

RETURN VALUE         top

       On success, this call returns 0 or a positive integer. On failure, it
       returns a negative errno-style error code.

ERRORS         top

       Returned errors may indicate the following problems:

       -EINVAL
           Specified parameter is invalid.

       -EPERM
           Message has been sealed.

       -ESTALE
           Message is in invalid state.

       -ENXIO
           Message cannot be appended to.

       -ENOMEM
           Memory allocation failed.

NOTES         top

       The sd_bus_append_basic() function described here is available 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_append(3), The D-Bus
       specification[2]

NOTES         top

        1. Basic Types
           http://dbus.freedesktop.org/doc/dbus-specification.html#basic-types

        2. The D-Bus specification
           http://dbus.freedesktop.org/doc/dbus-specification.html

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 2017-07-05.  If you dis‐
       cover 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 234                                   SD_BUS_MESSAGE_APPEND_BASIC(3)

Pages that refer to this page: sd-bus(3)sd_bus_message_append(3)sd_bus_message_append_array(3)sd_bus_message_append_string_memfd(3)sd_bus_message_append_strv(3)systemd.directives(7)systemd.index(7)