* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#ifndef LIBSERIALPORT_H
-#define LIBSERIALPORT_H
+/**
+ * @mainpage libserialport API
+ *
+ * Introduction
+ * ============
+ *
+ * libserialport is a minimal library written in C that is intended to take
+ * care of the OS-specific details when writing software that uses serial ports.
+ *
+ * By writing your serial code to use libserialport, you enable it to work
+ * transparently on any platform supported by the library.
+ *
+ * The operations that are supported are:
+ *
+ * - @ref Enumeration (obtaining a list of serial ports on the system)
+ * - @ref Ports
+ * - @ref Configuration (baud rate, parity, etc.)
+ * - @ref Data
+ * - @ref Errors
+ *
+ * libserialport is an open source project released under the LGPL3+ license.
+ *
+ * API principles
+ * ==============
+ *
+ * The API is simple, and designed to be a minimal wrapper around the serial
+ * port support in each OS.
+ *
+ * Most functions take a pointer to a struct sp_port, which represents a serial
+ * port. These structures are always allocated and freed by the library, using
+ * the functions in the @ref Enumeration "Enumeration" section.
+ *
+ * All functions can return only four possible error values:
+ *
+ * - @ref SP_ERR_ARG means that a function was called with invalid
+ * arguments. This implies a bug in the caller. The arguments passed would
+ * be invalid regardless of the underlying OS or serial device involved.
+ *
+ * - @ref SP_ERR_FAIL means that the OS reported a failure. The error code or
+ * message provided by the OS can be obtained by calling sp_last_error_code()
+ * or sp_last_error_message().
+ *
+ * - @ref SP_ERR_SUPP indicates that there is no support for the requested
+ * operation in the current OS, driver or device. No error message is
+ * available from the OS in this case. There is either no way to request
+ * the operation in the first place, or libserialport does not know how to
+ * do so in the current version.
+ *
+ * - @ref SP_ERR_MEM indicates that a memory allocation failed.
+ *
+ * All of these error values are negative.
+ *
+ * Function calls that succeed return @ref SP_OK, which is equal to zero,
+ * or where otherwise documented a positive value.
+ */
+
+#ifndef LIBSERIALPORT_LIBSERIALPORT_H
+#define LIBSERIALPORT_LIBSERIALPORT_H
#ifdef __cplusplus
extern "C" {
/* Package version macros (e.g. for conditional compilation). */
#define SP_PACKAGE_VERSION_MAJOR @SP_PACKAGE_VERSION_MAJOR@
#define SP_PACKAGE_VERSION_MINOR @SP_PACKAGE_VERSION_MINOR@
+#define SP_PACKAGE_VERSION_MICRO @SP_PACKAGE_VERSION_MICRO@
#define SP_PACKAGE_VERSION_STRING "@SP_PACKAGE_VERSION@"
/* Library/libtool version macros (e.g. for conditional compilation). */
#define SP_LIB_VERSION_AGE @SP_LIB_VERSION_AGE@
#define SP_LIB_VERSION_STRING "@SP_LIB_VERSION@"
-/* A serial port. */
-struct sp_port {
- /* Name used to open the port */
- char *name;
- /* OS-specific port handle */
-#ifdef _WIN32
- HANDLE hdl;
-#else
- int fd;
-#endif
-};
-
-/* Return values. */
-enum {
- /* Operation completed successfully. */
+/** Return values. */
+enum sp_return {
+ /** Operation completed successfully. */
SP_OK = 0,
- /* Invalid arguments were passed to the function. */
+ /** Invalid arguments were passed to the function. */
SP_ERR_ARG = -1,
- /* A system error occured while executing the operation. */
+ /** A system error occured while executing the operation. */
SP_ERR_FAIL = -2,
- /* A memory allocation failed while executing the operation. */
+ /** A memory allocation failed while executing the operation. */
SP_ERR_MEM = -3,
+ /** The requested operation is not supported by this system or device. */
+ SP_ERR_SUPP = -4,
};
-/* Port access modes. */
-enum {
- /* Open port for read/write access. */
- SP_MODE_RDWR = 1,
- /* Open port for read access only. */
- SP_MODE_RDONLY = 2,
- /* Open port in non-blocking mode. */
+/** Port access modes. */
+enum sp_mode {
+ /** Open port for read access. */
+ SP_MODE_READ = 1,
+ /** Open port for write access. */
+ SP_MODE_WRITE = 2,
+ /** Open port in non-blocking mode. */
SP_MODE_NONBLOCK = 4,
};
-/* Parity settings. */
-enum {
- /* No parity. */
+/** Buffer selection. */
+enum sp_buffer {
+ /** Input buffer. */
+ SP_BUF_INPUT = 1,
+ /** Output buffer. */
+ SP_BUF_OUTPUT = 2,
+ /** Both buffers. */
+ SP_BUF_BOTH = 3,
+};
+
+/** Parity settings. */
+enum sp_parity {
+ /** Special value to indicate setting should be left alone. */
+ SP_PARITY_INVALID = -1,
+ /** No parity. */
SP_PARITY_NONE = 0,
- /* Even parity. */
- SP_PARITY_EVEN = 1,
- /* Odd parity. */
- SP_PARITY_ODD = 2,
+ /** Odd parity. */
+ SP_PARITY_ODD = 1,
+ /** Even parity. */
+ SP_PARITY_EVEN = 2,
+};
+
+/** RTS pin behaviour. */
+enum sp_rts {
+ /** Special value to indicate setting should be left alone. */
+ SP_RTS_INVALID = -1,
+ /** RTS off. */
+ SP_RTS_OFF = 0,
+ /** RTS on. */
+ SP_RTS_ON = 1,
+ /** RTS used for flow control. */
+ SP_RTS_FLOW_CONTROL = 2,
+};
+
+/** CTS pin behaviour. */
+enum sp_cts {
+ /** Special value to indicate setting should be left alone. */
+ SP_CTS_INVALID = -1,
+ /** CTS ignored. */
+ SP_CTS_IGNORE = 0,
+ /** CTS used for flow control. */
+ SP_CTS_FLOW_CONTROL = 1,
+};
+
+/** DTR pin behaviour. */
+enum sp_dtr {
+ /** Special value to indicate setting should be left alone. */
+ SP_DTR_INVALID = -1,
+ /** DTR off. */
+ SP_DTR_OFF = 0,
+ /** DTR on. */
+ SP_DTR_ON = 1,
+ /** DTR used for flow control. */
+ SP_DTR_FLOW_CONTROL = 2,
+};
+
+/** DSR pin behaviour. */
+enum sp_dsr {
+ /** Special value to indicate setting should be left alone. */
+ SP_DSR_INVALID = -1,
+ /** DSR ignored. */
+ SP_DSR_IGNORE = 0,
+ /** DSR used for flow control. */
+ SP_DSR_FLOW_CONTROL = 1,
};
-/* Flow control settings. */
-enum {
- /* No flow control. */
- SP_FLOW_NONE = 0,
- /* Hardware (RTS/CTS) flow control. */
- SP_FLOW_HARDWARE = 1,
- /* Software (XON/XOFF) flow control. */
- SP_FLOW_SOFTWARE = 2,
+/** XON/XOFF flow control behaviour. */
+enum sp_xonxoff {
+ /** Special value to indicate setting should be left alone. */
+ SP_XONXOFF_INVALID = -1,
+ /** XON/XOFF disabled. */
+ SP_XONXOFF_DISABLED = 0,
+ /** XON/XOFF enabled for input only. */
+ SP_XONXOFF_IN = 1,
+ /** XON/XOFF enabled for output only. */
+ SP_XONXOFF_OUT = 2,
+ /** XON/XOFF enabled for input and output. */
+ SP_XONXOFF_INOUT = 3,
};
-int sp_get_port_by_name(const char *portname, struct sp_port **port_ptr);
+/** Standard flow control combinations. */
+enum sp_flowcontrol {
+ /** No flow control. */
+ SP_FLOWCONTROL_NONE = 0,
+ /** Software flow control using XON/XOFF characters. */
+ SP_FLOWCONTROL_XONXOFF = 1,
+ /** Hardware flow control using RTS/CTS signals. */
+ SP_FLOWCONTROL_RTSCTS = 2,
+ /** Hardware flow control using DTR/DSR signals. */
+ SP_FLOWCONTROL_DTRDSR = 3,
+};
+
+/** Input signals. */
+enum sp_signal {
+ /** Clear to send. */
+ SP_SIG_CTS = 1,
+ /** Data set ready. */
+ SP_SIG_DSR = 2,
+ /** Data carrier detect. */
+ SP_SIG_DCD = 4,
+ /** Ring indicator. */
+ SP_SIG_RI = 8,
+};
+
+/** A serial port. */
+struct sp_port;
+
+/** Configuration for a serial port. */
+struct sp_port_config {
+ /** Baud rate in bits per second. */
+ int baudrate;
+ /** Number of data bits to use. Valid values are 5 to 8. */
+ int bits;
+ /** Parity setting to use. */
+ enum sp_parity parity;
+ /** Number of stop bits to use (1 or 2). */
+ int stopbits;
+ /** RTS pin mode. */
+ enum sp_rts rts;
+ /** CTS pin mode. */
+ enum sp_cts cts;
+ /** DTR pin mode. */
+ enum sp_dtr dtr;
+ /** DSR pin mode. */
+ enum sp_dsr dsr;
+ /** XON/XOFF flow control mode. */
+ enum sp_xonxoff xon_xoff;
+};
+
+/**
+@defgroup Enumeration Port enumeration
+@{
+*/
+
+/**
+ * Obtain a pointer to a new sp_port structure representing the named port.
+ *
+ * The user should allocate a variable of type "struct sp_port *" and pass a
+ * pointer to this to receive the result.
+ *
+ * The result should be freed after use by calling sp_free_port().
+ *
+ * If any error is returned, the variable pointed to by port_ptr will be set
+ * to NULL. Otherwise, it will be set to point to the newly allocated port.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_port_by_name(const char *portname, struct sp_port **port_ptr);
+
+/**
+ * Get the name of a port.
+ *
+ * The name returned is whatever is normally used to refer to a port on the
+ * current operating system; e.g. for Windows it will usually be a "COMn"
+ * device name, and for Unix it will be a device path beginning with "/dev/".
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return The port name, or NULL if an invalid port is passed. The name
+ * string is part of the port structure and may not be used after the
+ * port structure has been freed.
+ */
+char *sp_get_port_name(const struct sp_port *port);
+
+/**
+ * Free a port structure obtained from sp_get_port_by_name() or sp_copy_port().
+ */
void sp_free_port(struct sp_port *port);
-int sp_list_ports(struct sp_port ***list_ptr);
-int sp_copy_port(const struct sp_port *port, struct sp_port **copy_ptr);
+
+/**
+ * List the serial ports available on the system.
+ *
+ * The result obtained is an array of pointers to sp_port structures,
+ * terminated by a NULL. The user should allocate a variable of type
+ * "struct sp_port **" and pass a pointer to this to receive the result.
+ *
+ * The result should be freed after use by calling sp_free_port_list().
+ * If a port from the list is to be used after freeing the list, it must be
+ * copied first using sp_copy_port().
+ *
+ * If any error is returned, the variable pointed to by list_ptr will be set
+ * to NULL. Otherwise, it will be set to point to the newly allocated array.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_list_ports(struct sp_port ***list_ptr);
+
+/**
+ * Make a new copy of a sp_port structure.
+ *
+ * The user should allocate a variable of type "struct sp_port *" and pass a
+ * pointer to this to receive the result.
+ *
+ * The copy should be freed after use by calling sp_free_port().
+ *
+ * If any error is returned, the variable pointed to by copy_ptr will be set
+ * to NULL. Otherwise, it will be set to point to the newly allocated copy.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_copy_port(const struct sp_port *port, struct sp_port **copy_ptr);
+
+/**
+ * Free a port list obtained from sp_list_ports().
+ *
+ * This will also free all the sp_port structures referred to from the list;
+ * any that are to be retained must be copied first using sp_copy_port().
+ */
void sp_free_port_list(struct sp_port **ports);
-int sp_open(struct sp_port *port, int flags);
-int sp_close(struct sp_port *port);
-int sp_flush(struct sp_port *port);
-int sp_write(struct sp_port *port, const void *buf, size_t count);
-int sp_read(struct sp_port *port, void *buf, size_t count);
-int sp_set_params(struct sp_port *port, int baudrate, int bits, int parity,
- int stopbits, int flowcontrol, int rts, int dtr);
+
+/**
+ * @}
+ * @defgroup Ports Opening and closing ports
+ * @{
+ */
+
+/**
+ * Open the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param flags Flags to use when opening the serial port.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_open(struct sp_port *port, enum sp_mode flags);
+
+/**
+ * Close the specified serial port.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_close(struct sp_port *port);
+
+/**
+ * @}
+ * @defgroup Configuration Setting port parameters
+ * @{
+ */
+
+/**
+ * Get the current configuration of the specified serial port.
+ *
+ * The user should allocate a struct sp_port_config, then pass a pointer to it
+ * as the config parameter. The struct will be populated with the port
+ * configuration.
+ *
+ * Any setting that is in a state not recognised or supported by
+ * libserialport will have its value set to -1 in the struct.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config(struct sp_port *port, struct sp_port_config *config);
+
+/**
+ * Set the configuration for the specified serial port.
+ *
+ * The user should populate a struct sp_port_config, then pass a pointer to it
+ * as the config parameter.
+ *
+ * To retain the current value of any setting, set that field to -1.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config(struct sp_port *port, const struct sp_port_config *config);
+
+/**
+ * Set the baud rate for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param baudrate Baud rate in bits per second.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_baudrate(struct sp_port *port, int baudrate);
+
+/**
+ * Set the number of data bits for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param bits Number of data bits to use. Valid values are 5 to 8.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_bits(struct sp_port *port, int bits);
+
+/**
+ * Set the parity for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param parity Parity setting to use.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_parity(struct sp_port *port, enum sp_parity parity);
+
+/**
+ * Set the number of stop bits for the specified port.
+ *
+ * @param port Pointer to port structure.
+ * @param stopbits Number of stop bits to use (1 or 2).
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_stopbits(struct sp_port *port, int stopbits);
+
+/**
+ * Set the flow control type for the specified serial port.
+ *
+ * This function is a wrapper that sets the RTS, CTS, DTR, DSR and
+ * XON/XOFF settings as necessary for the specified flow control
+ * type. For more fine-grained control of these settings, use their
+ * individual configuration functions or the sp_set_config() function.
+ *
+ * @param port Pointer to port structure.
+ * @param flowcontrol Flow control setting to use.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_flowcontrol(struct sp_port *port, enum sp_flowcontrol flowcontrol);
+
+/**
+ * Set the RTS pin behaviour for the specified port.
+ *
+ * @param port Pointer to port structure.
+ * @param rts RTS pin mode.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_rts(struct sp_port *port, enum sp_rts rts);
+
+/**
+ * Set the CTS pin behaviour for the specified port.
+ *
+ * @param port Pointer to port structure.
+ * @param cts CTS pin mode.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_cts(struct sp_port *port, enum sp_cts cts);
+
+/**
+ * Set the DTR pin behaviour for the specified port.
+ *
+ * @param port Pointer to port structure.
+ * @param dtr DTR pin mode.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_dtr(struct sp_port *port, enum sp_dtr dtr);
+
+/**
+ * Set the RTS pin behaviour for the specified port.
+ *
+ * @param port Pointer to port structure.
+ * @param dsr DSR pin mode.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_dsr(struct sp_port *port, enum sp_dsr dsr);
+
+/**
+ * Configure XON/XOFF flow control for the specified port.
+ *
+ * @param port Pointer to port structure.
+ * @param xon_xoff XON/XOFF flow control mode.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_xon_xoff(struct sp_port *port, enum sp_xonxoff xon_xoff);
+
+/**
+ * @}
+ * @defgroup Data Reading, writing, and flushing data
+ * @{
+*/
+
+/**
+ * Read bytes from the specified serial port.
+ *
+ * Note that this function may return after reading less than the specified
+ * number of bytes; it is the user's responsibility to iterate as necessary
+ * in this case.
+ *
+ * @param port Pointer to port structure.
+ * @param buf Buffer in which to store the bytes read.
+ * @param count Maximum number of bytes to read.
+ *
+ * @return The number of bytes read on success, or a negative error code.
+ */
+enum sp_return sp_read(struct sp_port *port, void *buf, size_t count);
+
+/**
+ * Write bytes to the specified serial port.
+ *
+ * Note that this function may return after writing less than the specified
+ * number of bytes; it is the user's responsibility to iterate as necessary
+ * in this case.
+ *
+ * @param port Pointer to port structure.
+ * @param buf Buffer containing the bytes to write.
+ * @param count Maximum number of bytes to write.
+ *
+ * @return The number of bytes written on success, or a negative error code.
+ */
+enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count);
+
+/**
+ * Flush serial port buffers. Data in the selected buffer(s) is discarded.
+ *
+ * @param port Pointer to port structure.
+ * @param buffers Which buffer(s) to flush.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers);
+
+/**
+ * Wait for buffered data to be transmitted.
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_drain(struct sp_port *port);
+
+/**
+ * @}
+ * @defgroup Signal Port signalling operations
+ * @{
+ */
+
+/**
+ * Gets the status of the control signals for the specified port.
+ *
+ * The user should allocate a variable of type "enum sp_signal" and pass a
+ * pointer to this variable to receive the result. The result is a bitmask
+ * in which individual signals can be checked by bitwise OR with values of
+ * the sp_signal enum.
+ *
+ * @param port Pointer to port structure.
+ * @param signals Pointer to variable to receive result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_signals(struct sp_port *port, enum sp_signal *signals);
+
+/**
+ * Put the port transmit line into the break state.
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_start_break(struct sp_port *port);
+
+/**
+ * Take the port transmit line out of the break state.
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_end_break(struct sp_port *port);
+
+/**
+ * @}
+ * @defgroup Errors Obtaining error information
+ * @{
+*/
+
+/**
+ * Get the error code for a failed operation.
+ *
+ * In order to obtain the correct result, this function should be called
+ * straight after the failure, before executing any other system operations.
+ *
+ * @return The system's numeric code for the error that caused the last
+ * operation to fail.
+ */
int sp_last_error_code(void);
+
+/**
+ * Get the error message for a failed operation.
+ *
+ * In order to obtain the correct result, this function should be called
+ * straight after the failure, before executing other system operations.
+ *
+ * @return The system's message for the error that caused the last
+ * operation to fail. This string may be allocated by the function,
+ * and should be freed after use by calling sp_free_error_message().
+ */
char *sp_last_error_message(void);
+
+/**
+ * Free an error message returned by sp_last_error_message().
+ */
void sp_free_error_message(char *message);
+/**
+ * Set the handler function for library debugging messages.
+ *
+ * Debugging messages are generated by the library during each operation,
+ * to help in diagnosing problems. The handler will be called for each
+ * message. The handler can be set to NULL to ignore all debug messages.
+ *
+ * The handler function should accept a format string and variable length
+ * argument list, in the same manner as e.g. printf().
+ *
+ * The default handler is sp_default_debug_handler().
+ */
+void sp_set_debug_handler(void (*handler)(const char *format, ...));
+
+/**
+ * Default handler function for library debugging messages.
+ *
+ * This function prints debug messages to the standard error stream if the
+ * environment variable LIBSERIALPORT_DEBUG is set. Otherwise, they are
+ * ignored.
+ */
+void sp_default_debug_handler(const char *format, ...);
+
+/** @} */
+
#ifdef __cplusplus
}
#endif
-#endif /* LIBSERIALPORT_H */
+#endif
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