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.
These APIs are implemented as a shared
  library, which can be compiled and linked to with the
  libsystemd pkg-config(1)
  file.