Table of Contents

Name

linx_send() - Send a LINX signal to a LINX endpoint (spid)

linx_send_w_s() - Send a LINX signal and specify a different LINX endpoint as sender

linx_send_w_opt() - Send a signal to a LINX endpoint (spid) with alternative

methods

Synopsis

#include <linx_types.h>
#include <linx.h>

int linx_send(LINX *linx, union LINX_SIGNAL **sig, LINX_SPID to);

int linx_send_w_s(LINX *linx, union LINX_SIGNAL **sig, LINX_SPID from, LINX_SPID to);

int linx_send_w_opt(LINX *linx, union LINX_SIGNAL **sig, LINX_SPID from, LINX_SPID to, int32_t *taglist);

Description

Send a signal to the LINX endpoint identified by the to binary identifier (spid). linx_send(3) always consumes the signal buffer, even if the call fails, by freeing the memory and setting *sig to LINX_NIL to prevent further access.

linx is the handle to the LINX endpoint, via which the signal is transmitted.


sig is the signal to send. The signal buffer must be owned by the transmitting LINX endpoint. It could have been allocated with linx_alloc(3) or received via the same LINX endpoint. If sig is corrupt, abort(3) is called.

to is the identifier (spid) of the recipient LINX endpoint, usually found as a result of a linx_hunt(3) . If the to spid refers to an endpoint that has been closed (i.e. in state LINX_ZOMBIE), -1 is returned and errno is set to ECONNRESET. If to does not apply to the specific method used in linx_send_w_opt(3) , the LINX_ILLEGAL_SPID define shall be used as its value.

from is the identifier (spid) of a different sender endpoint (instead of the transmitting endpoint). The recipient will see this spid as the sender of the signal. If the from spid refers to an endpoint that has been closed (i.e. in state LINX_ZOMBIE), -1 is returned and errno is set to ECONNRESET. If from does not apply to the specific method used in linx_send_w_opt(3) , the LINX_ILLEGAL_SPID define shall be used as its value.

taglist is an array of tags and values used with the call linx_send_w_opt(3) . Each tag has an associated value that directly follows it. See the example for details. If the taglist contains an invalid parameter, -1 is returned and errno is set to EINVAL. The taglist parameter list can contain the folllowing values.

LINX_SIG_OPT_OOB

The LINX_SIG_OPT_OOB tag is used to enable the OOB send method. The value of the LINX_SIG_OPT_OOB tag shall be 1.

An OOB signal is a signal that is transmitted, transported, forwarded and received ahead of in band signals. When the OOB signal is placed in the signal queue of the receiving process, it is placed ahead of in band signals but after OOB signals present in the signal queue.

If the OOB signal is sent inter node and the operating system on the receiving node is not supporting OOB, the signal is delivered as an in band signal.

When sending an OOB signal the sig parameter is the signal to be sent OOB. The signal buffer must be owned by the transmitting LINX endpoint. It could have been allocated with linx_alloc(3) or received.

When an OOB signal is sent using linx_send_w_opt(3) , a signal attribute is set on the signal, LINX_SIG_ATTR_OOB. The linx_sigattr(3) is used to test if the attribute is set or not.

LINX_SIG_OPT_END

Marks the end of the taglist and has no value. Must be at the end of the taglist.

Return Value

Returns 0 if successful. On failure, -1 is returned and errno will be set. In any case, sig is set to LINX_NIL.

Errors

EBADF, ENOTSOCK The LINX endpoint is associated with an invalid socket descriptor.

ENOBUFS, ENOMEM Insufficient memory is available.

ECONNRESET The destination spid refers to a LINX endpoint that has been closed (i.e. in state LINX_ZOMBIE). This situation is best avoided by using linx_attach(3) to supervise the receiving LINX endpoint. Closed spid are not reused until forced by spid instance counter overflow.

EPIPE This error is reported at an attempt to send to the spid of a LINX endpoint that is being closed as the call occurs.

EINVAL This error is reported if an unrecognized taglist parameter was passed in the taglist.

Bugs/Limitations

None.

Example


    union LINX_SIGNAL *sig;
    LINX *linx;
    LINX_SPID to_spid;
    LINX_SPID from_spid;
    int32_t taglist[3];
    ...
    taglist[0]=LINX_SIG_OPT_OOB;
    taglist[1]=1;
    taglist[2]=LINX_SIG_OPT_END;
    sig = linx_alloc(linx, sizeof(LINX_SIGSELECT), 100);
    (void)linx_send_w_opt(linx, &sig, to_spid, from_spid, taglist);
    ...

Notes

It is illegal to allocate/receive a signal buffer on one LINX endpoint and then send it using linx_send(3) from another LINX endpoint. In that case a new signal buffer needs to be allocated and the buffer contents moved to the new signal buffers prior to sending it. 

    union LINX_SIGNAL *sig1, *sig2;
    LINX_OSBUFSIZE size;
    LINX_SIGSELECT sel[] = {0};
    LINX *linx1, *linx2;
    LINX_SPID to_spid;
    ...
    sig1 = linx_receive(linx1, &sig1, sel);
    size = linx_sigsize(linx1, sig1);
    sig2 = linx_alloc(linx2, size, sel);
    memcpy((void)sig2, (void)sig1, size);
    (void)linx_free_buf(linx1, &sig1);
    (void)linx_send(linx2, &sig2, to_spid);
    ...

See Also

linx(7) , linx_alloc(3) , linx_hunt(3) , linx_receive(3) , linx_receive_w_tmo(3) , linx_receive_from(3) , linx_sigattr(3)

Author

Enea LINX team

Copyright

Copyright (c) 2006-2007, Enea Software AB All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. Neither the name of Enea Software AB nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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