'\" t
.TH "SD_BUS_MESSAGE_SET_EXPECT_REPLY" "3" "" "systemd 255" "sd_bus_message_set_expect_reply"
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.nh
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.\" * MAIN CONTENT STARTS HERE *
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.SH "NAME"
sd_bus_message_set_expect_reply, sd_bus_message_get_expect_reply, sd_bus_message_set_auto_start, sd_bus_message_get_auto_start, sd_bus_message_set_allow_interactive_authorization, sd_bus_message_get_allow_interactive_authorization \- Set and query bus message metadata
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-bus\&.h>
.fi
.ft
.HP \w'int\ sd_bus_message_set_expect_reply('u
.BI "int sd_bus_message_set_expect_reply(sd_bus_message\ *" "message" ", int\ " "b" ");"
.HP \w'int\ sd_bus_message_get_expect_reply('u
.BI "int sd_bus_message_get_expect_reply(sd_bus_message\ *" "message" ");"
.HP \w'int\ sd_bus_message_set_auto_start('u
.BI "int sd_bus_message_set_auto_start(sd_bus_message\ *" "message" ", int\ " "b" ");"
.HP \w'int\ sd_bus_message_get_auto_start('u
.BI "int sd_bus_message_get_auto_start(sd_bus_message\ *" "message" ");"
.HP \w'int\ sd_bus_message_set_allow_interactive_authorization('u
.BI "int sd_bus_message_set_allow_interactive_authorization(sd_bus_message\ *" "message" ", int\ " "b" ");"
.HP \w'int\ sd_bus_message_get_allow_interactive_authorization('u
.BI "int sd_bus_message_get_allow_interactive_authorization(sd_bus_message\ *" "message" ");"
.SH "DESCRIPTION"
.PP
\fBsd_bus_message_set_expect_reply()\fR
sets or clears the
\fBNO_REPLY_EXPECTED\fR
flag on the message
\fIm\fR\&. This flag matters only for method call messages and is used to specify that no method return or error reply is expected\&. It is ignored for other types\&. Thus, for a method call message, calling
.sp
.if n \{\
.RS 4
.\}
.nf
sd_bus_message_set_expect_reply(\&..., 0)
.fi
.if n \{\
.RE
.\}
.sp
sets the flag and suppresses the reply\&.
.PP
\fBsd_bus_message_get_expect_reply()\fR
checks if the
\fBNO_REPLY_EXPECTED\fR
flag is set on the message
\fIm\fR\&. It will return positive if it is not set, and zero if it is\&.
.PP
\fBsd_bus_message_set_auto_start()\fR
sets or clears the
\fBNO_AUTO_START\fR
flag on the message
\fIm\fR\&. When the flag is set, the bus must not launch an owner for the destination name in response to this message\&. Calling
.sp
.if n \{\
.RS 4
.\}
.nf
sd_bus_message_set_auto_start(\&..., 0)
.fi
.if n \{\
.RE
.\}
.sp
sets the flag\&.
.PP
\fBsd_bus_message_get_auto_start()\fR
checks if the
\fBNO_AUTO_START\fR
flag is set on the message
\fIm\fR\&. It will return positive if it is not set, and zero if it is\&.
.PP
\fBsd_bus_message_set_allow_interactive_authorization()\fR
sets or clears the
\fBALLOW_INTERACTIVE_AUTHORIZATION\fR
flag on the message
\fIm\fR\&. Setting this flag informs the receiver that the caller is prepared to wait for interactive authorization via polkit or a similar framework\&. Note that setting this flag does not guarantee that the receiver will actually perform interactive authorization\&. Also, make sure to set a suitable message timeout when using this flag since interactive authorization could potentially take a long time as it depends on user input\&. If
\fIb\fR
is non\-zero, the flag is set\&.
.PP
\fBsd_bus_message_get_allow_interactive_authorization()\fR
checks if the
\fBALLOW_INTERACTIVE_AUTHORIZATION\fR
flag is set on the message
\fIm\fR\&. It will return a positive integer if the flag is set\&. Otherwise, it returns zero\&.
.SH "RETURN VALUE"
.PP
On success, these functions return a non\-negative integer\&. On failure, they return a negative errno\-style error code\&.
.SS "Errors"
.PP
Returned errors may indicate the following problems:
.PP
\fB\-EINVAL\fR
.RS 4
The
\fImessage\fR
parameter is
\fBNULL\fR\&.
.RE
.PP
\fB\-EPERM\fR
.RS 4
The message
\fImessage\fR
is sealed when trying to set a flag\&.
.sp
The message
\fImessage\fR
has wrong type\&.
.RE
.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_message_set_expect_reply()\fR,
\fBsd_bus_message_get_expect_reply()\fR,
\fBsd_bus_message_set_auto_start()\fR, and
\fBsd_bus_message_get_auto_start()\fR
were added in version 240\&.
.PP
\fBsd_bus_message_set_allow_interactive_authorization()\fR
and
\fBsd_bus_message_get_allow_interactive_authorization()\fR
were added in version 246\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1),
\fBsd-bus\fR(3),
\fBsd_bus_set_description\fR(3)