comm.h File Reference

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Defines
#define	MAX_RETRIES   3
#define	MAX_MSG_SIZE   1024
#define	COMM_PERIOD_MS   50
#define	COMM_PERIOD_US   (COMM_PERIOD_MS*1000)
Functions
int	cartcomm_connect (char *host, int port)
	Connect to the cart.
void	cartcomm_disconnect (int sockfd)
	Disconnect from the cart.
int	cartcomm_synchronize (int sockfd)
	Synchronize with the cart.
int	cartcomm_connect_sync (char *host, int port)
	Connect and synchronize to the cart.
int	cartcomm_send_msg (int sockfd, char *buf)
	Send a message to the cart.
int	cartcomm_read_msg (int sockfd, char *buf, int bufsize)
	Read a message from the cart.

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Define Documentation

#define COMM_PERIOD_MS   50

Definition at line 7 of file comm.h.

#define COMM_PERIOD_US   (COMM_PERIOD_MS*1000)

Definition at line 8 of file comm.h. Referenced by drive().

#define MAX_MSG_SIZE   1024

Definition at line 5 of file comm.h. Referenced by cartcomm_read_msg().

#define MAX_RETRIES   3

Definition at line 4 of file comm.h.

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Function Documentation

int cartcomm_connect (  char *  host, int  port )

Connect to the cart. Parameters: host  host with which to connect port  port on which to connect Returns: socket's file descriptor number (or -1, on failure) Definition at line 25 of file comm.c. References DEBUG1, and DEBUG2. Referenced by cartcomm_connect_sync().

int cartcomm_connect_sync (  char *  host, int  port )

Connect and synchronize to the cart. Parameters: host  host with which to connect port  port on which to connect Returns: socket's file descriptor number (or -1, on failure) Definition at line 143 of file comm.c. References cartcomm_connect(), cartcomm_disconnect(), cartcomm_synchronize(), and DEBUG2. Referenced by drive().

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void cartcomm_disconnect (  int  sockfd  )

Disconnect from the cart. Parameters: sockfd  socket's file descriptor number Definition at line 85 of file comm.c. Referenced by cartcomm_connect_sync(), and drive().

int cartcomm_read_msg (  int  sockfd, char *  buf, int  bufsize )

Read a message from the cart. Parameters: sockfd  socket's file descriptor number buf  buffer to read into bufsize  size of buf in bytes Return values: 0  success -1  failure Note: This function takes care of a variety of problems associated with using TCP as a datagram delivery protocol. We will gurantee that on success, we have a full frame; partial frames are discarded. If we have fallen behind, we will skip frames to get the latest frame available. Warning: This function blocks. Our read will timeout after 2x the communication cycle's length. Definition at line 177 of file comm.c. References DEBUG1, and MAX_MSG_SIZE. Referenced by cartcomm_synchronize(), and drive().

int cartcomm_send_msg (  int  sockfd, char *  buf )

Send a message to the cart. Parameters: sockfd  socket's file descriptor number buf  buffer containing the message to send Return values: 0  success -1  failure Note: We will retry up to MAX_RETRIES times to send the message. Definition at line 240 of file comm.c. References DEBUG1. Referenced by cartcomm_synchronize(), and drive().

int cartcomm_synchronize (  int  sockfd  )

Synchronize with the cart. Synchronization means we exchange messages back and forth with each other until the cart is happy with our communications. Parameters: sockfd  socket's file descriptor number Return values: 0  success -1  failure Definition at line 96 of file comm.c. References cartcomm_decode_msg(), cartcomm_read_msg(), cartcomm_send_msg(), cframe_t, DEBUG1, DEBUG2, and cframe::status. Referenced by cartcomm_connect_sync().

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