ANSI C, C++

#include <dclck.h>
int  dc_lck_get (char *name, DCLONG lockmode,
                 DCLONG ownerflag, DCLONG flags)

K&R C

#include <dclck.h>
int  dc_lck_get (name, lockmode, ownerflag, flags)
char      *name;
DCLONG    lockmode;
DCLONG    ownerflag;
DCLONG    flags;

The function dc_lck_get() specifies lock for resources to be used by UAPs. Lock is managed in global transactions which are managed by the OpenTP1 transaction manager.

The lock specified by the function dc_lck_get() is released by lock release function (dc_lck_release_all() or dc_lck_release_byname()). The lock is also released when the synchronization point of the global transaction that called the function dc_lck_get() is acquired.

name

Specify the name of the resource for which lock is to be specified. The name can be specified with up to 16-byte alphanumeric characters. The OpenTP1 lock service manages the lock on the basis of the specified resource name. If a value less than 16 bytes is specified and a null character appears, the value before the null character is regarded as the resource name. If a value exceeding 16 bytes is specified, the value up to 16 bytes is regarded as the resource name. The excess bytes are truncated.

The lock service does not check the contents of the character string. Specify a logically correct name. If a value other than alphanumeric characters is used for a resource name, the deadlock information, the timeout information, and the lckls command might not be displayed normally.

lockmode

Specify a lock mode. The lock mode must be DCLCK_PR or DCLCK_EX. They cannot be specified at the same time.

DCLCK_PR

The resource is referenced. Other UAPs are permitted to reference the resource but are not permitted to update it.

DCLCK_EX

The resource is updated. Other UAPs are not permitted to reference or update the resource.

ownerflag

Specify DCLCK_OWNER_MIGRATE.

flags

Specify a flag concerning lock for the resource. The following values can be specified:

DCLCK_WAIT

If a UAP competes for the resource with another UAP, the UAP waits until the resource is released. If this flag is not set when UAPs compete for the resource, an error is returned.

DCLCK_TEST

Specify this flag to check whether the resource can be used. Note the following even if the function dc_lck_get() terminates normally when this flag is set:

Lock is not enabled for the resource specified for name.

DCNOFLAGS

No flag is set.