adjmsg.9

7号信令功能代码,为开源代码

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.TH ADJMSG 9 "2004/01/12 23:32:58" "LiS-2_16_18-8" "Linux STREAMS DDI/DKI"
.SH NAME
.B adjmsg
\- trim bytes from the front or back of a \fISTREAMS\fR message
.SH SYNOPSIS
.PP
.B #include <sys/stream.h>
.HP 8
.IB retval " = adjmsg(mblk_t *" mp ", int " length );
.SH DESCRIPTION
.PP
.BR adjmsg ()
trims
.IR "" abs( length )
bytes from a
.IR STREAMS (4)
message pointed to by
.IR mp .
.PP
If
.I length
is less than zero,
.BR adjmsg ()
will trim bytes from the head of the message.
.PP
If
.I length
is greater than zero,
.BR adjmsg ()
will trim bytes from the tail of the message.
.PP
Any message blocks that are completely trimmed by
.BR adjmsg ()
are not removed from the message, but have their
.IR b_wptr 's
set to their
.IR b_rptr 's;
that is, the length of the data they contain is set to zero (0).
.SH "RETURN VALUES"
.PP
.BR adjmsg ()
returns one (1) on success and zero (0) on failure.
.SH ERRORS
.PP
If
.I mp
is a null pointer,
.I length
is greated that the message size, or if the bytes to trim crosses message blocks of
differing types,
.BR adjmsg ()
will fail and
.I retval
will be zero (0).
.SH CAVEATS
.PP
Note that the LiS
.[
LiS
.]
version of
.BR adjmsg ()
will not fail due to allocation errors.  Failures depend only on the
characteristics of the passed in message referenced by
.I mp
and the provided
.IR length .
.SH "SEE ALSO"
.PP
.BR msgpullup (9),
.BR pullupmsg (9).
.SH HISTORY
.PP
.BR adjmsg ()
first appeared in SVR 4.
.[
svr4
.]
.[
svr4
.]
.SH VERSIONS
.PP
This manpage was written for
.B LiS\c
.
.[
LiS
.]
.PP
.\"
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svr42
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.[
svr4
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