VEX Link C++ API¶

Note

PROS currently officially supports the use of one VEX Radio per brain for VEXLink.

pros::Link
- Constructor(s)
- Functions
Enumerated Values

pros::Link ¶

Constructor(s)¶

pros::Link(const std::uint8_t port, const std::string link_id, link_type_e_t type, bool ov = false);

#define LINK_TRANSMITTER_PORT 1
#define LINK_ID "ROBOT1"

 void initialize() {
    pros::Link transmitter(LINK_TRANSMITTER_PORT, LINK_ID, pros::E_LINK_TRANSMITTER);
 }

Parameters
port	The port of the radio for the intended link.
link_id	Unique link ID in the form of a string.
type	Indicates whether the radio link on the brain is a transmitter or reciever.
ov	Indicates if the radio on the given port needs vexlink to override the controller radio.

Functions ¶

connected ¶

Checks if a radio link on a port is active or not.

This function uses the following values of errno when an error state is reached:

ENXIO - The given value is not within the range of V5 ports (1-21).
ENODEV - The port cannot be configured as a radio.
ENXIO - The sensor is still calibrating, or no link is connected via the radio.

bool connected()

#define LINK_TRANSMITTER_PORT 1

void opcontrol() {
   pros::Link transmitter(LINK_TRANSMITTER_PORT);

   while (true) {
      if (transmitter.connected()) {
         pros::lcd::set_text(1, "Link connected!");
      }
      pros::delay(20);
   }
}

Returns: If a radio is connected to a port and it’s connected to a link.

raw_receivable_size()¶

Returns the bytes of data number of without protocol available to be read

This function uses the following values of errno when an error state is reached:

ENXIO - The given value is not within the range of V5 ports (1-21).
ENODEV - The port cannot be configured as a radio.
ENXIO - The sensor is still calibrating, or no link is connected via the radio.

std::uint32_t raw_receivable_size()

#define LINK_RECEIVER_PORT 1

void opcontrol() {
   pros::Link receiver(LINK_RECEIVER_PORT);

   std::uint32_t receivable_size = receiver.raw_receivable_size();
   pros::lcd::set_text(1, "Link receivable_size:");
   pros::lcd::set_text(2, std::to_string(receivable_size));
}

Returns: PROS_ERR if port is not a link/radio, else the bytes available to be read by the user.

raw_transmittable_size ¶

Returns the bytes of data available in transmission buffer.

This function uses the following values of errno when an error state is reached:

ENXIO - The given value is not within the range of V5 ports (1-21).
ENODEV - The port cannot be configured as a radio.
ENXIO - The sensor is still calibrating, or no link is connected via the radio.

std::uint32_t raw_transmittable_size( )

#define LINK_TRANSMITTER_PORT 1

void opcontrol() {
   pros::Link transmitter(LINK_TRANSMITTER_PORT);

   std::uint32_t transmittable_size = transmitter.raw_transmittable_size();
   pros::lcd::set_text(1, "Link transmittable_size:");
   pros::lcd::set_text(2, std::to_string(transmittable_size));
}

Returns: PROS_ERR if port is not a link/radio.

transmit_raw ¶

Send raw serial data through vexlink.

This function uses the following values of errno when an error state is reached:

ENXIO - The given value is not within the range of V5 ports (1-21).
ENODEV - The port cannot be configured as a radio.
ENXIO - The sensor is still calibrating, or no link is connected via the radio.
EBUSY - The transmitter buffer is still busy with a previous transmission.
EINVAL - The destination given is NULL, or the size given is larger than the FIFO buffer or destination buffer.

std::uint32_t transmit_raw( void* data, std::uint16_t data_size )

#define LINK_TRANSMITTER_PORT 1

void opcontrol() {
   pros::Link transmitter(LINK_TRANSMITTER_PORT);
   char* data = "Hello!";

   transmitter.transmit_raw((void*)data, sizeof(*data) * sizeof(data));
}

Parameters
data	Buffer with data to send
data_size	Buffer with data to send

Returns: PROS_ERR if port is not a link, 0 if the link is busy, and 1 if it succeeded.

receive_raw ¶

Receive raw serial data through vexlink.

This function uses the following values of errno when an error state is reached:

ENXIO - The given value is not within the range of V5 ports (1-21).
ENODEV - The port cannot be configured as a radio.
ENXIO - The sensor is still calibrating, or no link is connected via the radio.
EBUSY - The transmitter buffer is still busy with a previous transmission.
EINVAL - The destination given is NULL, or the size given is larger than the FIFO buffer or destination buffer.

std::uint32_t receive_raw( void* data, std::uint16_t data_size )

#define LINK_RECEIVER_PORT 1

void opcontrol() {
   char* result;
   char* expected = "Hello!";
   pros::Link receiver(LINK_RECEIVER_PORT);

   receiver.receive_raw((void*)result, sizeof(*expected) * sizeof(expected));
}

Parameters
dest	Destination buffer to read data to
data_size	Bytes of data to be read to the destination buffer

Returns: PROS_ERR if port is not a link, 0 if the link is busy, and 1 if it succeeded.

transmit ¶

Send packeted message through vexlink, with a checksum and start byte.

This function uses the following values of errno when an error state is reached:

ENXIO - The given value is not within the range of V5 ports (1-21).
ENODEV - The port cannot be configured as a radio.
ENXIO - The sensor is still calibrating, or no link is connected via the radio.
EBUSY - The transmitter buffer is still busy with a previous transmission.
EINVAL - The data given is NULL

std::uint32_t transmit( void* data, std::uint16_t data_size )

#define LINK_TRANSMITTER_PORT 1

void opcontrol() {
   pros::Link transmitter(LINK_TRANSMITTER_PORT);
   char* data = "Hello!";

   transmitter.transmit((void*)data, sizeof(*data) * sizeof(data));
}

Parameters
data	Destination buffer to read data to
data_size	Bytes of data to be read to the destination buffer

Returns: PROS_ERR if port is not a link, 0 if the link is busy, and the successfully transmitted size if it succeeded.

receive ¶

Receive packeted message through vexlink, with a checksum and start byte.

This function uses the following values of errno when an error state is reached:

ENXIO - The given value is not within the range of V5 ports (1-21).
ENODEV - The port cannot be configured as a radio.
ENXIO - The sensor is still calibrating, or no link is connected via the radio.
EBUSY - The transmitter buffer is still busy with a previous transmission.
EINVAL - The destination given is NULL, or the size given is larger than the FIFO buffer or destination buffer.
EBADMSG - Protocol error related to start byte, data size, or checksum.

std::uint32_t receive( void* dest, std::uint16_t data_size )

#define LINK_RECEIVER_PORT 1

void opcontrol() {
   char* result;
   char* expected = "Hello!";
   pros::Link receiver(LINK_RECEIVER_PORT);

   receiver.receive((void*)result, sizeof(*expected) * sizeof(expected));
}

Parameters
data	Destination buffer to read data to
data_size	Bytes of data to be read to the destination buffer

Returns: PROS_ERR if port is not a link or protocol error, 0 if the link is busy, and successfully received size if it succeeded.

clear_receive_buf ¶

Clear the receive buffer of the link, and discarding the data.

This function uses the following values of errno when an error state is reached:

ENXIO - The given value is not within the range of V5 ports (1-21).
ENODEV - The port cannot be configured as a radio.
ENXIO - The sensor is still calibrating, or no link is connected via the radio.

std::uint32_t clear_receive_buf()

#define LINK_TRANSMITTER_PORT 1

void opcontrol() {
   pros::Link transmitter(LINK_TRANSMITTER_PORT);
   char* data = "Hello!";

   transmitter.transmit((void*)data, sizeof(*data) * sizeof(data));

   transmitter.clear_receive_buf();
}

Returns: PROS_ERR if port is not a link, 1 if the operation succeeded.

Enumerated Values ¶

typedef enum link_type_e {
  E_LINK_RECEIVER = 0,
  E_LINK_TRANSMITTER,
  E_LINK_RX = E_LINK_RECEIVER,
  E_LINK_TX = E_LINK_TRANSMITTER
} link_type_e_t;

Value
E_LINK_RECEIVER	Indicating that the radio is a receiver.
E_LINK_RX	Indicating that the radio is a receiver.
E_LINK_TRANSMITTER	Indicating that the radio is a transmitter.
E_LINK_TX	Indicating that the radio is a transmitter.