put_user和get_user的使用

1. put_user Name put_user --    Write a simple value into user space. Synopsis put_user ( x, ptr); Arguments x Value to copy to user space. ptr Destination address, in user space. Context User context only. This function may sleep. Description This macro copies a single simple value from kernel space to user space. It supports simple types like char and int, but not larger data types like structures or arrays. ptr must have pointer-to-simple-variable type, and x must be assignable to the result of dereferencing ptr. Returns zero on success, or -EFAULT on error. 2. get_user Name get_user --    Get a simple variable from user space. Synopsis get_user ( x, ptr); Arguments x Variable to store result. ptr Source address, in user space. Context User context only. This function may sleep. Description This macro copies a single simple variable from user space to kernel space. It supports simple types like char and int, but not larger data types like structures or arrays. ptr must have pointer-to-simple-variable type, and the result of dereferencing ptr must be assignable to x without a cast. Returns zero on success, or -EFAULT on error. On error, the variable x is set to zero.