Select API#

fd_mask#

typedef long int fd_mask

A type representing a set of file descriptors.

select#

int select (int nfds, fd_set *restrict readfds, fd_set *restrict writefds, fd_set *restrict exceptfds, struct timeval *restrict timeout)

Monitor multiple file descriptors for readiness.

Returns

• On success, returns the total number of bits set in readfds, writefds. If the time limit expires, select() returns zero. On error, -1 is returned, and errno is set appropriately.

This function monitors multiple file descriptors, waiting until one or more of the file descriptors are ready for an I/O operation.

Note

• This implementation does not handle exceptfds.

sl_wisun_check_read_sockfd_set#

void sl_wisun_check_read_sockfd_set (void )

Check the read socket file descriptor set.

This function notifies select to check the read socket file descriptor set. The function should be called in response to the reception of SL_WISUN_MSG_SOCKET_DATA_AVAILABLE_IND_ID. It notifies select to check the read socket file descriptor set for any ready socket to read.

Usage:

// Application indication handler
void sl_wisun_on_event(void) {
  // Application code here...
  switch (evt->header.id) {
    // When SL_WISUN_MSG_SOCKET_DATA_AVAILABLE_IND_ID is received
    case SL_WISUN_MSG_SOCKET_DATA_AVAILABLE_IND_ID:
      // Call the function to check the read socket file descriptor set
      sl_wisun_check_read_sockfd_set();
      break;
  }
  // Application code here...
}

sl_wisun_check_write_sockfd_set#

void sl_wisun_check_write_sockfd_set (void )

Check the write socket file descriptor set.

This function notifies select to check the write socket file descriptor set. The function should be called in response to the reception of SL_WISUN_MSG_SOCKET_DATA_SENT_IND_ID. It notifies select to check the write socket file descriptor set for any ready socket to write.

Usage:

void sl_wisun_on_event(void) {
  // Your code here...
  switch (evt->header.id) {
    // When SL_WISUN_MSG_SOCKET_DATA_SENT_IND_ID is received
    case SL_WISUN_MSG_SOCKET_DATA_SENT_IND_ID:
      // Call the function to check the write socket file descriptor set
      sl_wisun_check_write_sockfd_set();
      break;
  }
  // Your code here...
}

sl_wisun_select_init#

void sl_wisun_select_init (void )

Initialize the select system.

This function initializes the select system by creating a new event flag with the specified attributes. The event flag is used to indicate when a file descriptor set is ready to be checked for I/O operations.

FD_CLR#

#define FD_CLR

(d, set)

Clear the bit for the file descriptor d in the fd_set.

FD_ELT#

#define FD_ELT

(d)

Calculate the index in the fds_bits array for the file descriptor d.

Returns

• The index in the fds_bits array.

FD_ISSET#

#define FD_ISSET

(d, set)

Check whether the bit for the file descriptor d is set in the fd_set.

Returns

• Nonzero if the bit is set, and zero otherwise.

FD_MASK#

#define FD_MASK

(d)

Create a mask for the bit position within an fd_mask for the file descriptor d.

Returns

• The mask for the bit position.

FD_SET#

#define FD_SET

(d, set)

Set the bit for the file descriptor d in the fd_set.

FD_SETSIZE#

#define FD_SETSIZE

64

Maximum number of file descriptors in ‘fd_set’.

FD_ZERO#

#define FD_ZERO

(set)

Clear all bits in the fd_set.

NFDBITS#

#define NFDBITS

(8 * (int) sizeof (fd_mask))

The number of bits in an fd_mask.