adjmsg(D3)adjmsg(D3)NAMEadjmsg - trim bytes from a message
SYNOPSIS
#include <sys/stream.h>
#include <sys/ddi.h>
int adjmsg(mblk_t *mp, int len);
Arguments
mp Pointer to the message to be trimmed.
len The number of bytes to be removed.
DESCRIPTIONadjmsg removes bytes from a message.
Return Values
If the message can be trimmed successfully, 1 is returned. Otherwise, 0
is returned.
USAGE
|len| (the absolute value of len) specifies how many bytes are to be
removed. If len is greater than 0, bytes are removed from the head of
the message. If len is less than 0, bytes are removed from the tail.
adjmsg fails if |len| is greater than the number of bytes in mp. If len
spans more than one message block in the message, the messages blocks
must be the same type, or else adjmsg will fail.
If len is greater than the amount of data in a single message block, that
message block is not freed. Rather, it is left linked in the message,
and its read and write pointers are set equal to each other, indicating
no data present in the block.
Level
Base or Interrupt.
Synchronization Constraints
Does not sleep.
Driver-defined basic locks, read/write locks, and sleep locks may be held
across calls to this function.
REFERENCESmsgb(D4)
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