Open System Services System Calls Reference Manual (G06.29+, H06.08+, J06.03+)

SPT_READLOCKX(2) OSS System Calls Reference Manual
NAME
SPT_READLOCKX - Sequentially locks and reads records in a Guardian disk file
LIBRARY
G-series native OSS processes: /G/system/sysnn/zsptsrl
H-series OSS processes: /G/system/zdllnnn/zsptdll
SYNOPSIS
[#include <cextdecs.h>]
#include <spthread.h>
short SPT_READLOCKX (
short filenum,
char *buffer,
unsigned short read_count,
[unsigned short *count_read ],
[long tag ]
);
PARAMETERS
filenum specifies the file number of a Guardian file open instance that identifies the file to
be read.
buffer specifies an array in the application process in which the information read from
the file is returned.
read_count specifies the number of bytes to be read.
count_read is for waited I/O only. This parameter returns a count of the number of bytes
returned from the file into buffer.
tag is for nowait I/O only. The tag value you define uniquely identifies the operation
associated with this call.
This parameter is supported only for program compatibility; if you provide it, it
is ignored.
DESCRIPTION
The SPT_READLOCKX() function is the thread-aware version of the Guardian READLOCKX
procedure.
The SPT_ READLOCKX() function sequentially locks and reads records in a Guardian disk
file, exactly like the combination of an SPT_LOCKREC() and SPT_READX() call.
SPT_READLOCKX() is intended for use with 32-bit extended addresses. Therefore, the data
buffer for SPT_READLOCKX() can be either in the caller’s stack segment or any extended
data segment.
For programming information about the READLOCKX procedure, see the Enscribe
Programmer’s Guide and the Guardian Programmer’s Guide.
Considerations
Nowait I/O and SPT_READLOCKX()
If the SPT_READLOCKX() function is used to initiate an operation with a file
opened for nowait I/O, it must complete with a corresponding call to the Guar-
dian AWAITIOX procedure.
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