sd_bus_message_append_string_memfd - Man Page

#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​.

All functions listed here are thread-agnostic and only a single thread may operate on a given object at any given time​. Different threads may access the same object at different times​. Multiple independent objects may be used from different threads in parallel​.

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​.

systemd(1), sd-bus(3), sd_bus_message_append_basic(3), The D-Bus specification​^[1]

1.

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

sd-bus(3), systemd.directives(7), systemd.index(7).

The man pages sd_bus_message_append_string_iovec(3) and sd_bus_message_append_string_space(3) are aliases of sd_bus_message_append_string_memfd(3).