USNEWLOCK(3P)                                                    USNEWLOCK(3P)


NAME
     usnewlock - allocate and initialize a lock

C SYNOPSIS
     #include <ulocks.h>

     ulock_t usnewlock (usptr_t *handle);

DESCRIPTION
     usnewlock allocates a lock from the arena designated by handle (returned
     from usinit(3P)) and initializes it and all associated data.  There are
     different types of locks; by default the fastest lock type for the class
     of machine the process is running on is allocated.  See usconfig(3P) for
     other specifiable lock types.  Metering and debugging are only enabled if
     the locks are of the debugging type (see usconfig(3P).  There is a limit
     of a maximum of 4096 locks per shared area (for hardware supported
     locks).  The size of the shared arena can also limit the number of locks
     that can be allocated.

     usnewlock will fail if one or more of the following are true:

     [ENOMEM]       There is no memory in the arena available to allocate the
                    lock structure (see usconfig(3P)).

     [ENOSPC]       If the system imposed maximum (4096) number of allocatable
                    locks has been exceeded.

     [ENOSPC]       All the locks in the system have been allocated.

SEE ALSO
     usconfig(3P), usctllock(3P), usfreelock(3P), usinit(3P), usinitlock(3P),
     usnewsema(3P), usnewpollsema(3P), ussetlock(3P).

DIAGNOSTICS
     Upon successful completion, a ulock_t structure is returned, otherwise
     NULL is returned and errno is set to indicate the error.


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