sd_bus_message_append_string_memfd, sd_bus_message_append_string_iovec, sd_bus_message_append_string_space — Attach a string to a message
#include <systemd/sd-bus.h>
int sd_bus_message_append_string_memfd( | sd_bus_message *m, |
int memfd) ; |
int sd_bus_message_append_string_iovec( | sd_bus_message *m, |
const struct iovec *iov, | |
unsigned n) ; |
int sd_bus_message_append_string_space( | sd_bus_message *m, |
size_t size, | |
char **s) ; |
The functions
sd_bus_message_append_string_memfd()
and
sd_bus_message_append_string_iovec()
can be
used to append a single string (item of type "s
")
to message m
.
In case of
sd_bus_message_append_string_memfd()
, the
contents of memfd
are the string. They must
satisfy the same constraints as described for the
"s
" type in
sd_bus_message_append_basic(3).
In case of
sd_bus_message_append_string_iovec()
, the
payload of iov
is the string. It must
satisfy the same constraints as described for the
"s
" type in
sd_bus_message_append_basic(3).
The iov
argument must point to
n
struct iovec
structures. Each structure may have the
iov_base field set, in which case the
memory pointed to will be copied into the message, or unset, in
which case a block of spaces (ASCII 32) of length
iov_len will be inserted. The
memory pointed at by iov
may be changed
after this call.
The
sd_bus_message_append_string_space()
function appends
space for a string to message m
. It behaves
similar to sd_bus_message_append_basic()
with
type "s
", but instead of copying a string into
the message, it returns a pointer to the destination area to
the caller in pointer p
. Space for the string
of length size
plus the terminating
NUL
is allocated.
On success, those calls return 0 or a positive integer. On failure, they return a negative errno-style error code.
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.