adjmsg(9f) - osol9

1adjmsg(9F)               Kernel Functions for Drivers               adjmsg(9F)
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NAME

6       adjmsg - trim bytes from a message
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SYNOPSIS

9       #include <sys/stream.h>
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13       int adjmsg(mblk_t *mp, ssize_t len);
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INTERFACE LEVEL

17       Architecture independent level 1 (DDI/DKI).
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PARAMETERS

20       mp     Pointer to the message to be trimmed.
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23       len    The number of bytes to be removed.
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DESCRIPTION

27       The adjmsg() function removes bytes from a message. |len| (the absolute
28       value of len) specifies the number of bytes to be removed. The adjmsg()
29       function only trims bytes across message blocks of the same type.
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32       The  adjmsg()  function  finds  the maximal leading sequence of message
33       blocks of the same type as that of mp and starts removing bytes  either
34       from  the  head  of that sequence or from the tail of that sequence. If
35       len is greater than 0, adjmsg() removes bytes from  the  start  of  the
36       first message block in that sequence. If len is less than 0, it removes
37       bytes from the end of the last message block in that sequence.
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40       The adjmsg() function fails if |len| is  greater  than  the  number  of
41       bytes in the maximal leading sequence it finds.
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44       The  adjmsg() function may remove any except the first zero-length mes‐
45       sage block created during adjusting. It may also remove any zero-length
46       message blocks that occur within the scope of |len|.
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RETURN VALUES

49       The adjmsg() function returns:
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51       1    Successful completion.
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54       0    An error occurred.
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CONTEXT

58       The  adjmsg()  function  can  be called from user, interrupt, or kernel
59       context.
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