Digital

NAME

atomic_op − perform test and set operation. 

SYNOPSIS

#include <sys/lock.h>

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

PARAMETERS

opThis 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. 

addrThis is the target address of the operation. 

DESCRIPTION

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

Whether or not this function is executed as a system call is hardware-dependent. 

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. 

ERRORS

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

[EINVAL] The op is not a valid operation type, or addr is not aligned on an integer boundary. 

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

[EFAULT] An error occurred during reading or writing the location specified by addr.