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LSSETBUF.C
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1989-08-30
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/* Copyright (c) 1989 Citadel */
/* All Rights Reserved */
/* #ident "lssetbuf.c 1.1 - 89/07/03" */
#include <blkio.h>
#include <errno.h>
#include "lseq_.h"
/*man---------------------------------------------------------------------------
NAME
lssetbuf - assign buffering to an lseq
SYNOPSIS
#include <lseq.h>
int lssetbuf(lsp, buf)
lseq_t *lsp;
void *buf;
DESCRIPTION
The lssetbuf function causes the storage area pointed to by buf to be
used by lseq lsp instead of an automatically allocated buffer area. If
buf is the NULL pointer, lsp will be completely unbuffered.
The size of the storage area needed can be obtained using the
LSBUFSIZE() macro:
char buf[LSBUFSIZE(RECSIZE, LSBUFCNT)];
.
.
.
lssetbuf(lsp, (void *)buf);
where RECSIZE is the size of the records in the lseq and LSBUFCNT is
the default number of records buffered when an lseq is opened.
LSBUFCNT is #defined in lseq.h. If the number of records buffered has
been changed using lssetvbuf, then that number should be used in place
of LSBUFCNT.
Any previously buffered data is written out before installing the new
buffer area.
lssetbuf will fail if one or more of the following is true:
[EINVAL] lsp is not a valid lseq pointer.
[LSENBUF] buf is not the NULL pointer and lsp
is not buffered.
[LSENOPEN] lsp is not open.
SEE ALSO
lssetvbuf, lssync.
DIAGNOSTICS
Upon successful completion, a value of 0 is returned. Otherwise, a
value of -1 is returned, and errno set to indicate the error.
------------------------------------------------------------------------------*/
int lssetbuf(lsp, buf)
lseq_t * lsp;
void * buf;
{
int rs = 0;
errno = 0;
/* validate arguments */
if (!ls_valid(lsp)) {
errno = EINVAL;
return -1;
}
/* check if not open */
if (!(lsp->flags & LSOPEN)) {
errno = LSENOPEN;
return -1;
}
/* assign buffering */
rs = bsetbuf(lsp->bp, buf);
if (rs == -1) {
if (errno == BENBUF) errno = LSENBUF;
LSEPRINT;
return -1;
}
errno = 0;
return 0;
}