atomic_op(2) [ultrix man page]

atomic_op(2)							System Calls Manual						      atomic_op(2)

Name
       atomic_op - perform test and set operation.

Syntax
       #include <sys/lock.h>

       int atomic_op(op, addr)
       int op;
       int *addr;

Arguments
       op	      This argument is the operation type.  If the operation type is ATOMIC_SET, this call specifies the test and set operation on
		      location addr.  If the operation type is ATOMIC_CLEAR, this call specifies the clear operation on location addr.

       addr	      This is the target address of the operation.

Description
       The call provides test and set operation at a user address.

       For RISC systems, is executed as a system call.	For VAX systems, a system call is not executed for this library function.

Return Values
       If the atomic_op operation succeeds, then 0 is returned.  Otherwise a -1 is returned, and a more specific error code is stored in errno.

Diagnostics
       [EBUSY]	      The location specified by addr is already set.

       [EINVAL]       The op is not a valid operation type.

       [EACCES]       The address specified in addr is not write accessible.

       [EALIGN]       The addr is not on an integer boundary.

																      atomic_op(2)

SHMAT(2)						      BSD System Calls Manual							  SHMAT(2)

NAME

     shmat, shmdt -- attach or detach shared memory

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sys/types.h>
     #include <sys/ipc.h>
     #include <sys/shm.h>

     void *
     shmat(int shmid, const void *addr, int flag);

     int
     shmdt(const void *addr);

DESCRIPTION

     The shmat() system call attaches the shared memory segment identified by shmid to the calling process's address space.  The address where the
     segment is attached is determined as follows:

     o	 If addr is 0, the segment is attached at an address selected by the kernel.

     o	 If addr is nonzero and SHM_RND is not specified in flag, the segment is attached the specified address.

     o	 If addr is specified and SHM_RND is specified, addr is rounded down to the nearest multiple of SHMLBA.

     The shmdt() system call detaches the shared memory segment at the address specified by addr from the calling process's address space.

RETURN VALUES

     Upon success, shmat() returns the address where the segment is attached; otherwise, -1 is returned and errno is set to indicate the error.

     The shmdt() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate
     the error.

ERRORS

     The shmat() system call will fail if:

     [EINVAL]		No shared memory segment was found corresponding to shmid.

     [EINVAL]		The addr argument was not an acceptable address.

     The shmdt() system call will fail if:

     [EINVAL]		The addr argument does not point to a shared memory segment.

SEE ALSO

     shmctl(2), shmget(2)

BSD
								  August 2, 1995							       BSD