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#ifndef FLOW_H
#define FLOW_H
#ifdef __cplusplus
extern "C" {
#endif
#include <stdbool.h>
#include <stddef.h>
// general error codes, whose that are returned by functions
#define E_IO 1 // IO error
#define E_ACCESS_DENIED 2 // access denied
#define E_BUSY 3 // port is busy
#define E_INVALID_SETTINGS 4 // some port settings are invalid
#define E_INTERRUPT 5 // not really an error, function call aborted because port is closed
#define E_NO_PORT 6 // requested port does not exist
#define PARITY_NONE 0
#define PARITY_ODD 1
#define PARITY_EVEN 2
/**
* Contains internal configuration of an open serial port.
*/
struct serial_config;
/**
* Opens a serial port and allocates memory for storing configuration. Note: if this function fails,
* any internally allocated resources will be freed.
* @param port_name name of port
* @param baud baud rate
* @param char_size character size of data transmitted through serial device
* @param two_stop_bits set to use two stop bits instead of one
* @param parity kind of parity checking to use
* @param serial pointer to memory that will be allocated with a serial structure
* @return 0 on success
* @return -E_NO_PORT if the given port does not exist
* @return -E_ACCESS_DENIED if permissions are not sufficient to open port
* @return -E_BUSY if port is already in use
* @return -E_INVALID_SETTINGS if any of the specified settings are invalid
* @return -E_IO on other error
*/
int serial_open(
const char* port_name,
int baud,
int char_size,
bool two_stop_bits,
int parity,
struct serial_config** const serial);
/**
* Closes a previously opened serial port and frees memory containing the configuration. Note: after a call to
* this function, the 'serial' pointer will become invalid, make sure you only call it once. This function is NOT
* thread safe, make sure no read or write is in prgress when this function is called (the reason is that per
* close manual page, close should not be called on a file descriptor that is in use by another thread).
* @param serial pointer to serial configuration that is to be closed (and freed)
* @return 0 on success
* @return -E_IO on error
*/
int serial_close(struct serial_config* const serial);
/**
* Starts a read from a previously opened serial port. The read is blocking, however it may be
* interrupted by calling 'serial_cancel_read' on the given serial port.
* @param serial pointer to serial configuration from which to read
* @param buffer buffer into which data is read
* @param size maximum buffer size
* @return n>0 the number of bytes read into buffer
* @return -E_INTERRUPT if the call to this function was interrupted
* @return -E_IO on IO error
*/
int serial_read(struct serial_config* const serial, char* const buffer, size_t size);
/**
* Cancels a blocked read call. This function is thread safe, i.e. it may be called from a thread even
* while another thread is blocked in a read call.
* @param serial_config the serial port to interrupt
* @return 0 on success
* @return -E_IO on error
*/
int serial_cancel_read(struct serial_config* const serial);
/**
* Writes data to a previously opened serial port. Non bocking.
* @param serial pointer to serial configuration to which to write
* @param data data to write
* @param size number of bytes to write from data
* @return n>0 the number of bytes written
* @return -E_IO on IO error
*/
int serial_write(struct serial_config* const serial, char* const data, size_t size);
/**
* Sets debugging option. If debugging is enabled, detailed error message are printed from method calls.
*/
void serial_debug(bool value);
#ifdef __cplusplus
}
#endif
#endif /* FLOW_H */
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