systemd/man/sd_bus_request_name.3
2015-02-17 11:22:16 +01:00

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.TH "SD_BUS_REQUEST_NAME" "3" "" "systemd 219" "sd_bus_request_name"
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.SH "NAME"
sd_bus_request_name, sd_bus_release_name \- Request or release a well\-known name on a bus
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-bus\&.h>
.fi
.ft
.HP \w'int\ sd_bus_request_name('u
.BI "int sd_bus_request_name(sd_bus\ *" "bus" ", const\ char\ *" "name" ", uint64_t\ " "flags" ");"
.HP \w'int\ sd_bus_release_name('u
.BI "int sd_bus_release_name(sd_bus\ *" "bus" ", const\ char\ *" "name" ");"
.SH "DESCRIPTION"
.PP
\fBsd_bus_request_name()\fR
requests a well\-known name on a bus\&. It takes a bus connection, a valid bus name and a flags parameter\&. The flags parameter is a combination of the following flags:
.PP
\fISD_BUS_NAME_ALLOW_REPLACEMENT\fR
.RS 4
After acquiring the name successfully, permit other peers to take over the name when they try to acquire it with the
\fISD_BUS_NAME_REPLACE_EXISTING\fR
flag set\&. If
\fISD_BUS_NAME_ALLOW_REPLACEMENT\fR
is not set on the original request, such a request by other peers will be denied\&.
.RE
.PP
\fISD_BUS_NAME_REPLACE_EXISTING\fR
.RS 4
Take over the name if it is already acquired by another peer, and that other peer has permitted takeover by setting
\fISD_BUS_NAME_ALLOW_REPLACEMENT\fR
while acquiring it\&.
.RE
.PP
\fISD_BUS_NAME_QUEUE\fR
.RS 4
Queue the acquisition of the name when the name is already taken\&.
.RE
.PP
\fBsd_bus_release_name()\fR
releases an acquired well\-known name\&. It takes a bus connection and a valid bus name as parameters\&.
.SH "RETURN VALUE"
.PP
On success, these calls return 0 or a positive integer\&. On failure, these calls return a negative errno\-style error code\&.
.PP
If
\fISD_BUS_NAME_QUEUE\fR
is specified,
\fBsd_bus_request_name()\fR
will return 0 when the name is already taken by another peer and the client has been added to the queue for the name\&. In that case, the caller can subscribe to
"NameOwnerChanged"
signals to be notified when the name is successfully acquired\&.
\fBsd_bus_request_name()\fR
returns > 0 when the name has immediately been acquired successfully\&.
.SH "ERRORS"
.PP
Returned errors may indicate the following problems:
.PP
\fB\-EALREADY\fR
.RS 4
The caller already is the owner of the specified name\&.
.RE
.PP
\fB\-EEXIST\fR
.RS 4
The name has already been acquired by a different peer, and SD_BUS_NAME_REPLACE_EXISTING was not specified or the other peer did not specify SD_BUS_NAME_ALLOW_REPLACEMENT while acquiring the name\&.
.RE
.PP
\fB\-ESRCH\fR
.RS 4
It was attempted to release a name that is currently not registered on the bus\&.
.RE
.PP
\fB\-EADDRINUSE\fR
.RS 4
It was attempted to release a name that is owned by a different peer on the bus\&.
.RE
.PP
\fB\-EINVAL\fR
.RS 4
A specified parameter is invalid\&.
.RE
.PP
\fB\-ENOTCONN\fR
.RS 4
The bus connection has been disconnected\&.
.RE
.PP
\fB\-ECHILD\fR
.RS 4
The bus connection has been created in a different process than the current one\&.
.RE
.SH "NOTES"
.PP
The
\fBsd_bus_acquire_name()\fR
and
\fBsd_bus_release_name()\fR
interfaces are available as a shared library, which can be compiled and linked to with the
\fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
file\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1),
\fBsd-bus\fR(3),
\fBsd_bus_new\fR(3)