'\" t
.TH "SD_BUS_MESSAGE_DUMP" "3" "" "systemd 261.2" "sd_bus_message_dump"
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.SH "NAME"
sd_bus_message_dump, sd_bus_message_dump_json \- Produce a string representation of a message for debugging purposes
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-bus\&.h>
.fi
.ft
.HP \w'int\ sd_bus_message_dump('u
.BI "int sd_bus_message_dump(sd_bus_message\ *" "m" ", FILE\ *" "f" ", uint64_t\ " "flags" ");"
.HP \w'int\ sd_bus_message_dump_json('u
.BI "int sd_bus_message_dump_json(sd_bus_message\ *" "m" ", uint64_t\ " "flags" ", sd_json_variant\ **" "ret" ");"
.SH "DESCRIPTION"
.PP
The
\fBsd_bus_message_dump()\fR
function writes a textual representation of the message
\fIm\fR
to the stream
\fIf\fR\&. If
\fIf\fR
is
\fBNULL\fR, standard output (\fBstdio\fR) will be used\&. This function is intended to be used for debugging purposes, and the output is neither stable nor designed to be machine readable\&.
.PP
The
\fBsd_bus_message_dump_json()\fR
function converts the DBus message
\fIm\fR
to a JSON variant and stores it in
\fIret\fR\&. The caller should call
\fBsd_json_variant_unref()\fR
for the acquired JSON variant after use\&. Unlike
\fBsd_bus_message_dump()\fR, the function itself does not print anything\&. To print the DBus message in the JSON format, please pass the returned JSON variant to
\fBsd_json_variant_dump()\fR\&.
.PP
The
\fIflags\fR
parameter may be used to modify the output, and is a combination of zero or more of the following flags:
.PP
\fBSD_BUS_MESSAGE_DUMP_WITH_HEADER\fR
.RS 4
The header of the message that specifies the message type, flags, and several more additional metadata will be printed or included in the resulting JSON object\&.
.RE
.PP
\fBSD_BUS_MESSAGE_DUMP_SUBTREE_ONLY\fR
.RS 4
Only the current container will be printed or converted\&. When the flag is
\fInot\fR
specified, the contents of the whole message will be printed or converted\&.
.RE
.PP
Note that these functions move the read pointer of the message\&. It may be necessary to reset the position afterwards, for example with
\fBsd_bus_message_rewind\fR(3)\&.
.SH "EXAMPLES"
.PP
Output for a signal message (with
\fBSD_BUS_MESSAGE_DUMP_WITH_HEADER\fR):
.sp
.if n \{\
.RS 4
.\}
.nf
>\& Type=signal  Endian=l  Flags=1  Version=1  Cookie=22
  Path=/value/a  Interface=org\&.freedesktop\&.DBus\&.Properties  Member=PropertiesChanged
  MESSAGE "sa{sv}as" {
          STRING "org\&.freedesktop\&.systemd\&.ValueTest";
          ARRAY "{sv}" {
                  DICT_ENTRY "sv" {
                          STRING "Value";
                          VARIANT "s" {
                                  STRING "object 0x1e, path /value/a";
                          };
                  };
          };
          ARRAY "s" {
                  STRING "Value2";
                  STRING "AnExplicitProperty";
          };
  };
.fi
.if n \{\
.RE
.\}
.sp
.SH "RETURN VALUE"
.PP
On success, this function returns 0 or a positive integer\&. On failure, it returns a negative errno\-style error code\&. No error codes are currently defined\&.
.SH "NOTES"
.PP
Functions described here are available as a shared library, which can be compiled against and linked to with the
\fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
file\&.
.PP
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\&.
.PP
The code described here uses
\fBgetenv\fR(3), which is declared to be not multi\-thread\-safe\&. This means that the code calling the functions described here must not call
\fBsetenv\fR(3)
from a parallel thread\&. It is recommended to only do calls to
\fBsetenv()\fR
from an early phase of the program when no other threads have been started\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1), \fBsd-bus\fR(3), \fBsd-json\fR(3)