clnt_control()
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A function macro to change or retrieve various information
about a client object.
The
req
argument
indicates the type of operation, and
info
is a pointer to the information.
For both connectionless and connection-oriented transports,
the supported values of
req
and their argument types and what they do are:
CLSET_TIMEOUT | struct timeval * | set total timeout |
CLGET_TIMEOUT | struct timeval * | get total timeout |
Note:
if you set the timeout using
clnt_control(),
the timeout argument passed by
clnt_call()
is ignored in all subsequent calls.
Note:
If you set the timeout value to 0,
clnt_control()
immediately returns an error
( RPC_TIMEDOUT).
Set the timeout argument to 0 for batching calls.
CLGET_SVC_ADDR | struct netbuf * | get servers address |
CLGET_FD | int * | get fd from handle |
CLSET_FD_CLOSE | void | close fd on destroy |
CLSET_FD_NCLOSE | void | do not close fd on destroy |
CLGET_VERS | uint32_t * | get RPC program version |
CLSET_VERS | uint32_t * | set RPC program version |
CLGET_XID | uint32_t * | get XID of previous call |
CLSET_XID | uint32_t * | set XID of next call |
The following operations are valid for connectionless transports only:
CLSET_RETRY_TIMEOUT | struct timeval * | set the retry timeout |
CLGET_RETRY_TIMEOUT | struct timeval * | get the retry timeout |
CLSET_CONNECT | int * | useconnect(2) |
The retry timeout is the time that RPC
waits for the server to reply before retransmitting the request.
The
clnt_control()
function
returns
TRUE
on success and
FALSE
on failure.
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clnt_create()
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Generic client creation routine for program
prognum
and version
versnum.
The
host
argument
identifies the name of the remote host where the server
is located.
The
nettype
argument
indicates the class of transport protocol to use.
The transports are tried in left to right order in
NETPATH
environment variable or in top to bottom order in
the netconfig database.
The
clnt_create()
function
tries all the transports of the
nettype
class available from the
NETPATH
environment variable and the netconfig database,
and chooses the first successful one.
A default timeout is set and can be modified using
clnt_control().
This routine returns
NULL
if it fails.
The
clnt_pcreateerror()
routine can be used to print the reason for failure.
Note:
clnt_create()
returns a valid client handle even
if the particular version number supplied to
clnt_create()
is not registered with the
rpcbind(8)
service.
This mismatch will be discovered by a
clnt_call()
later (see
rpc_clnt_calls(3)).
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clnt_create_timed()
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Generic client creation routine which is similar to
clnt_create()
but which also has the additional argument
timeout
that specifies the maximum amount of time allowed for
each transport class tried.
In all other respects, the
clnt_create_timed()
call behaves exactly like the
clnt_create()
call.
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clnt_create_vers()
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Generic client creation routine which is similar to
clnt_create()
but which also checks for the
version availability.
The
host
argument
identifies the name of the remote host where the server
is located.
The
nettype
argument
indicates the class transport protocols to be used.
If the routine is successful it returns a client handle created for
the highest version between
vers_low
and
vers_high
that is supported by the server.
The
vers_outp
argument
is set to this value.
That is, after a successful return
vers_low
<=
*vers_outp
<=
vers_high.
If no version between
vers_low
and
vers_high
is supported by the server then the routine fails and returns
NULL.
A default timeout is set and can be modified using
clnt_control().
This routine returns
NULL
if it fails.
The
clnt_pcreateerror()
routine can be used to print the reason for failure.
Note:
clnt_create()
returns a valid client handle even
if the particular version number supplied to
clnt_create()
is not registered with the
rpcbind(8)
service.
This mismatch will be discovered by a
clnt_call()
later (see
rpc_clnt_calls(3)).
However,
clnt_create_vers()
does this for you and returns a valid handle
only if a version within
the range supplied is supported by the server.
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clnt_create_vers_timed()
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Generic client creation routine which is similar to
clnt_create_vers()
but which also has the additional argument
timeout
that specifies the maximum amount of time allowed for
each transport class tried.
In all other respects, the
clnt_create_vers_timed()
call behaves exactly like the
clnt_create_vers()
call.
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clnt_destroy()
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A function macro that destroys the client's RPC handle.
Destruction usually involves deallocation
of private data structures, including
clnt
itself.
Use of
clnt
is undefined after calling
clnt_destroy().
If the RPC library opened the associated file descriptor, or
CLSET_FD_CLOSE
was set using
clnt_control(),
the file descriptor will be closed.
The caller should call
auth_destroy(clnt->cl_auth)
(before calling
clnt_destroy())
to destroy the associated
AUTH
structure (see
rpc_clnt_auth(3)).
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clnt_dg_create()
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This routine creates an RPC client for the remote program
prognum
and version
versnum;
the client uses a connectionless transport.
The remote program is located at address
svcaddr.
The
fildes
argument
is an open and bound file descriptor.
This routine will resend the call message in intervals of
15 seconds until a response is received or until the
call times out.
The total time for the call to time out is specified by
clnt_call()
(see
clnt_call()
in
rpc_clnt_calls(3)).
The retry time out and the total time out periods can
be changed using
clnt_control().
The user may set the size of the send and receive
buffers with the
sendsz
and
recvsz
arguments;
values of 0 choose suitable defaults.
This routine returns
NULL
if it fails.
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clnt_pcreateerror()
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Print a message to standard error indicating
why a client RPC handle could not be created.
The message is prepended with the string
s
and a colon, and appended with a newline.
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clnt_spcreateerror()
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Like
clnt_pcreateerror(),
except that it returns a string
instead of printing to the standard error.
A newline is not appended to the message in this case.
Warning:
returns a pointer to a buffer that is overwritten
on each call.
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clnt_raw_create()
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This routine creates an RPC
client handle for the remote program
prognum
and version
versnum.
The transport used to pass messages to the service is
a buffer within the process's address space,
so the corresponding RPC
server should live in the same address space;
(see
svc_raw_create()
in
rpc_svc_create(3)).
This allows simulation of RPC and measurement of
RPC overheads, such as round trip times,
without any kernel or networking interference.
This routine returns
NULL
if it fails.
The
clnt_raw_create()
function
should be called after
svc_raw_create().
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clnt_tli_create()
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This routine creates an RPC
client handle for the remote program
prognum
and version
versnum.
The remote program is located at address
svcaddr.
If
svcaddr
is
NULL
and it is connection-oriented, it is assumed that the file descriptor
is connected.
For connectionless transports, if
svcaddr
is
NULL,
RPC_UNKNOWNADDR
error is set.
The
fildes
argument
is a file descriptor which may be open, bound and connected.
If it is
RPC_ANYFD,
it opens a file descriptor on the transport specified by
netconf.
If
fildes
is
RPC_ANYFD
and
netconf
is
NULL,
a
RPC_UNKNOWNPROTO
error is set.
If
fildes
is unbound, then it will attempt to bind the descriptor.
The user may specify the size of the buffers with the
sendsz
and
recvsz
arguments;
values of 0 choose suitable defaults.
Depending upon the type of the transport (connection-oriented
or connectionless),
clnt_tli_create()
calls appropriate client creation routines.
This routine returns
NULL
if it fails.
The
clnt_pcreateerror()
routine can be used to print the reason for failure.
The remote rpcbind
service (see
rpcbind(8))
is not consulted for the address of the remote
service.
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clnt_tp_create()
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Like
clnt_create()
except
clnt_tp_create()
tries only one transport specified through
netconf.
The
clnt_tp_create()
function
creates a client handle for the program
prognum,
the version
versnum,
and for the transport specified by
netconf.
Default options are set,
which can be changed using
clnt_control()
calls.
The remote rpcbind service on the host
host
is consulted for the address of the remote service.
This routine returns
NULL
if it fails.
The
clnt_pcreateerror()
routine can be used to print the reason for failure.
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clnt_tp_create_timed()
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Like
clnt_tp_create()
except
clnt_tp_create_timed()
has the extra argument
timeout
which specifies the maximum time allowed for
the creation attempt to succeed.
In all other respects, the
clnt_tp_create_timed()
call behaves exactly like the
clnt_tp_create()
call.
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clnt_vc_create()
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This routine creates an RPC
client for the remote program
prognum
and version
versnum;
the client uses a connection-oriented transport.
The remote program is located at address
svcaddr.
The
fildes
argument
is an open and bound file descriptor.
The user may specify the size of the send and receive buffers
with the
sendsz
and
recvsz
arguments;
values of 0 choose suitable defaults.
This routine returns
NULL
if it fails.
The address
svcaddr
should not be
NULL
and should point to the actual address of the remote program.
The
clnt_vc_create()
function
does not consult the remote rpcbind service for this information.
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struct rpc_createerr rpc_createerr;
A global variable whose value is set by any RPC
client handle creation routine
that fails.
It is used by the routine
clnt_pcreateerror()
to print the reason for the failure.
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