'\" t
.TH "SD_BUS_GET_CURRENT_HANDLER" "3" "" "systemd 255" "sd_bus_get_current_handler"
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.SH "NAME"
sd_bus_get_current_handler, sd_bus_get_current_message, sd_bus_get_current_slot, sd_bus_get_current_userdata \- Query information of the callback a bus object is currently running
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-bus\&.h>
.fi
.ft
.HP \w'typedef\ int\ (*sd_bus_message_handler_t)('u
.BI "typedef int (*sd_bus_message_handler_t)(sd_bus_message\ *" "m" ", void\ *" "userdata" ", sd_bus_error\ *" "ret_error" ");"
.HP \w'sd_bus_message_handler_t\ sd_bus_get_current_handler('u
.BI "sd_bus_message_handler_t sd_bus_get_current_handler(sd_bus\ *" "bus" ");"
.HP \w'sd_bus_message*\ sd_bus_get_current_message('u
.BI "sd_bus_message* sd_bus_get_current_message(sd_bus\ *" "bus" ");"
.HP \w'sd_bus_slot*\ sd_bus_get_current_slot('u
.BI "sd_bus_slot* sd_bus_get_current_slot(sd_bus\ *" "bus" ");"
.HP \w'void*\ sd_bus_get_current_userdata('u
.BI "void* sd_bus_get_current_userdata(sd_bus\ *" "bus" ");"
.SH "DESCRIPTION"
.PP
Whenever sd\-bus is about to invoke a user\-supplied callback function, it stores the current callback, D\-Bus message, slot and userdata pointer and allows these to be queried via
\fBsd_bus_get_current_handler()\fR,
\fBsd_bus_get_current_message()\fR,
\fBsd_bus_get_current_slot()\fR
and
\fBsd_bus_get_current_userdata()\fR, respectively\&. If
\fIbus\fR
cannot be resolved or if execution does not reside in a user\-supplied callback of
\fIbus\fR, these functions return
\fBNULL\fR\&.
.SH "RETURN VALUE"
.PP
On success, these functions return the requested object\&. On failure, they return
\fBNULL\fR\&.
.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
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 "HISTORY"
.PP
\fBsd_bus_get_current_handler()\fR,
\fBsd_bus_get_current_message()\fR,
\fBsd_bus_get_current_slot()\fR, and
\fBsd_bus_get_current_userdata()\fR
were added in version 246\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1),
\fBsd-bus\fR(3)