Check if any sockets are ready for available read or write operations or error conditions.

Files

net_sock.h/net_sock.c net_bsd.h/net_bsd.c

Prototypes

NET_SOCK_RTN_CODE NetSock_Sel(NET_SOCK_QTY      sock_nbr_max,
                              NET_SOCK_DESC    *p_sock_desc_rd,
                              NET_SOCK_DESC    *p_sock_desc_wr,
                              NET_SOCK_DESC    *p_sock_desc_err,
                              NET_SOCK_TIMEOUT *p_timeout,
                              NET_ERR          *p_err);

int               select     (       int        desc_nbr_max,
                              struct fd_set    *p_desc_rd,
                              struct fd_set    *p_desc_wr,
                              struct fd_set    *p_desc_err,
                              struct timeval   *p_timeout);

Arguments

sock_nbr_max

Specifies the maximum number of socket file descriptors in the file descriptor sets.

p_sock_desc_rd

Pointer to a set of socket file descriptors to:

- Check for available read operations.
- Returns the actual socket file descriptors ready for available read operations, if no errors;
- Returns the initial, non-modified set of socket file descriptors, on any errors;
- Returns a null-valued (i.e., zero-cleared) descriptor set, if any timeout expires.

p_sock_desc_wr

Pointer to a set of socket file descriptors to:

- Check for available read operations.
- Returns the actual socket file descriptors ready for available write operations, if no errors;
- Returns the initial, non-modified set of socket file descriptors, on any errors;
- Returns a null-valued (i.e., zero-cleared) descriptor set, if any timeout expires.

p_sock_desc_err

Pointer to a set of socket file descriptors to:

- Check for any available socket errors.
- Returns the actual socket file descriptors ready with any pending errors;
- Returns the initial, non-modified set of socket file descriptors, on any errors;
- Returns a null-valued (i.e., zero-cleared) descriptor set, if any timeout expires.

p_timeout

Pointer to a timeout argument.

p_err

Pointer to variable that will receive the error code from this function:

NET_SOCK_ERR_NONE NET_SOCK_ERR_TIMEOUT NET_INIT_ERR_NOT_COMPLETED NET_SOCK_ERR_INVALID_DESC NET_SOCK_ERR_INVALID_TIMEOUT NET_SOCK_ERR_INVALID_SOCK NET_SOCK_ERR_INVALID_TYPE NET_SOCK_ERR_NOT_USED NET_SOCK_ERR_EVENTS_NBR_MAX NET_ERR_FAULT_LOCK_ACQUIRE

Returned Value

Returns the number of sockets ready with available operations, if successful;

NET_SOCK_BSD_RTN_CODE_TIMEOUT/0, upon timeout;

NET_SOCK_BSD_ERR_SEL/-1, otherwise.

Required Configuration

Available only if NET_SOCK_CFG_SEL_EN is enabled (see section Socket Layer Configuration).

Notes / Warnings

Supports socket file descriptors only (i.e., socket ID numbers).

The descriptor macro’s is used to prepare and decode socket file descriptor sets (see macro functions in section Network Socket Functions).

See “net_sock.c NetSock_Sel() Note #3” for more details.

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