sd_bus_message_copy - Copy the contents of one message to another
sd_bus_message_copy() copies the contents from message source to
m. If all is false, a single complete type is copied (basic or
container). If all is true, the contents are copied until the end of
the currently open container or the end of source.
On success, this call returns true if anything was copied, and false if there
was nothing to copy. On failure, it returns a negative errno-style error code.
Returned errors may indicate the following problems:
source or m are NULL.
Message m has been sealed or source has
not been sealed.
Destination message is in invalid state.
Destination message cannot be appended to.
Memory allocation failed.
These APIs are implemented as a shared library, which can be compiled and linked
to with the libsystemd pkg-config(1) file.