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Name

linx_alloc() - Allocate a signal buffer on a LINX endpoint

Synopsis

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

union LINX_SIGNAL *linx_alloc(LINX *linx, LINX_OSBUFSIZE size, LINX_SIGSELECT sig_no);

Description

linx_alloc() is used to allocate a signal buffer of the indicated size The first 4 bytes of the signal buffer are initialized with the provided signal number sig_no. The signal number can be replaced later by writing a new value in the first 4 bytes of the buffer.

The new buffer is owned by the LINX endpoint with which it was created. The ownership is transferred to the receiving LINX endpoint when the signal is successfully sent using linx_send(3) . If the signal is not sent, the owner must free the buffer by calling linx_free_buf(3) using the same linx handle. The buffer will be freed if the owning LINX endpoint is closed or the process owning the endpoint exits.

linx is the handle to the LINX endpoint.

size is the size in bytes of the new signal buffer. The minimum size is 4 bytes, needed to store the signal number.

sig_no is the signal number stored at the beginning of the signal buffer.

Return Value

On success, a pointer to the allocated signal buffer is returned. On error, LINX_NIL is returned and errno will be set.

Errors

EMSGSIZE The size is invalid.

ENOMEM Insufficient memory is available.

Bugs/Limitations

None.

Notes

A LINX signal can be only be sent by the LINX endpoint that owns it, i.e. the endpoint it was created from or received on. It can not be reused and sent by another LINX endpoint.

If a process, which has allocated signal buffers, calls fork(2) , both instances will own copies of the signal buffers. As only one process may use a LINX endpoint and its resources, either the parent or the child MUST close the LINX endpoint using linx_close(3) .

See Also

linx(7) , linx_close(3) , linx_free_buf(3) , linx_hunt(3) , linx_send(3) , fork(2)

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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