Solvline PB2xxxUG - Manual (Page 81)

U_read_port
Read Serial Data
Description This function reads a number of bytes (less than or equal to buff_size) from a
specified file descriptor and places them in buff.
Synopsis int U_read_port (int fd, char *buff, int buff_size, int mtu_size)
Parameters fd : Serial file descriptor
buff : Pointer to buffer to receive bytes
buff_size : The maximum size of bytes to read into buffer
mtu_size : The maximum of a packet that can be transferred in one
frame over a network (maximum size : 1100)
Returns 0 : If end of file
n : The number of bytes read (between 1 and buff_size)
U_send_port
Send Serial Data
Description The function attempts to write the specified number of bytes from the
specified buffer to the specified serial file descriptor.
Synopsis int U_send_port (int fd, char *buff, int length)
Parameters fd : Serial file descriptor
buff : Pointer to buffer to write
length : Length of buffer
Returns n : The number of bytes sent
81