sd_bus_message_append_basic — Attach a single part to a message
#include <systemd/sd-bus.h>
int sd_bus_message_append_basic( | sd_bus_message *m, |
| char type, | |
char void *p); |
sd_bus_message_append_basic appends a
single item to the message m. Parameter
type determines how pointer
p is interpreted.
type must be one of the basic types
as defined by the
Basic Types
section of the D-Bus specification, and listed in the table below.
Table 1. Item format specifiers
| Specifier | Constant | Description | Size |
|---|---|---|---|
"y" | SD_BUS_TYPE_BYTE | unsigned integer | 1 byte |
"b" | SD_BUS_TYPE_BOOLEAN | boolean | 4 bytes |
"n" | SD_BUS_TYPE_INT16 | signed integer | 2 bytes |
"q" | SD_BUS_TYPE_UINT16 | unsigned integer | 2 bytes |
"i" | SD_BUS_TYPE_INT32 | signed integer | 4 bytes |
"u" | SD_BUS_TYPE_UINT32 | unsigned integer | 4 bytes |
"x" | SD_BUS_TYPE_INT64 | signed integer | 8 bytes |
"t" | SD_BUS_TYPE_UINT64 | unsigned integer | 8 bytes |
"d" | SD_BUS_TYPE_DOUBLE | floating-point | 8 bytes |
"s" | SD_BUS_TYPE_STRING | Unicode string | variable |
"o" | SD_BUS_TYPE_OBJECT_PATH | object path | variable |
"g" | SD_BUS_TYPE_SIGNATURE | signature | variable |
"h" | SD_BUS_TYPE_UNIX_FD | UNIX file descriptor | 4 bytes |
The value of the parameter is copied into the memory area
containing the message and may be changed after this call. If
type is "h" (UNIX file
descriptor), it is always "consumed" by this call, and either
successfully appended to the message or closed.
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.
On success, this call returns 0 or a positive integer. On failure, it returns a negative errno-style error code.
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.