/* * This file is part of the libserialport project. * * Copyright (C) 2013 Martin Ling * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program. If not, see . */ /** * * @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 three possible error values. @ref SP_ERR_ARG * indicates the function was called with invalid arguments. @ref SP_ERR_FAIL * indicates that the OS reported a failure. @ref SP_ERR_MEM indicates that a * memory allocation failed. All of these error values are negative. * * When @ref SP_ERR_FAIL is returned, an error code or string description of * the error can be obtained by calling sp_last_error_code() or * sp_last_error_message(). The error code or message is that provided by the * OS; libserialport does not define any error codes or messages of its own. * * Function calls that succeed return @ref SP_OK, which is equal to zero, * or where otherwise documented a positive value. */ #ifndef LIBSERIALPORT_H #define LIBSERIALPORT_H #ifdef __cplusplus extern "C" { #endif #include #ifdef _WIN32 #include #endif /* 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_STRING "@SP_PACKAGE_VERSION@" /* Library/libtool version macros (e.g. for conditional compilation). */ #define SP_LIB_VERSION_CURRENT @SP_LIB_VERSION_CURRENT@ #define SP_LIB_VERSION_REVISION @SP_LIB_VERSION_REVISION@ #define SP_LIB_VERSION_AGE @SP_LIB_VERSION_AGE@ #define SP_LIB_VERSION_STRING "@SP_LIB_VERSION@" /** Return values. */ enum sp_return { /** Operation completed successfully. */ SP_OK = 0, /** Invalid arguments were passed to the function. */ SP_ERR_ARG = -1, /** A system error occured while executing the operation. */ SP_ERR_FAIL = -2, /** A memory allocation failed while executing the operation. */ SP_ERR_MEM = -3, }; /** 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, }; /** 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, /** 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, }; /** 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, }; /** 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 { /** Name used to open the port. */ char *name; /** @cond 0 */ /** OS-specific port handle. */ #ifdef _WIN32 HANDLE hdl; #else int fd; #endif /** @endcond */ }; /** 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(). * * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation * failure, or SP_ERR_ARG if an invalid pointer is passed. 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. */ enum sp_return sp_get_port_by_name(const char *portname, struct sp_port **port_ptr); /** * Free a port structure obtained from sp_get_port_by_name() or sp_copy_port(). */ void sp_free_port(struct sp_port *port); /** * 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(). * * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation * failure, or SP_ERR_ARG if an invalid pointer is passed. 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. */ 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(). * * @return SP_OK on success, SP_ERR_MEM on allocation failure, or SP_ERR_ARG * if an invalid port or pointer is passed. 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. */ 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); /** * @} * @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 on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation * failure, or SP_ERR_ARG if an invalid port is passed. */ enum sp_return sp_open(struct sp_port *port, enum sp_mode flags); /** * Close the specified serial port. * * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * if an invalid port is passed. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * for invalid arguments. */ 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, SP_ERR_FAIL on failure, * or SP_ERR_ARG for invalid arguments. */ 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, SP_ERR_FAIL on failure, * or SP_ERR_ARG for invalid arguments. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * if an invalid port is passed. */ enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers); /** * Wait for buffered data to be transmitted. * * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * if an invalid port is passed. */ 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 on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * if an an invalid port or pointer is passed. */ enum sp_return sp_get_signals(struct sp_port *port, enum sp_signal *signals); /** * Put the port transmit line into the break state. * * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * if an invalid port is passed. */ enum sp_return sp_start_break(struct sp_port *port); /** * Take the port transmit line out of the break state. * * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG * if an invalid port is passed. */ 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); /** @} */ #ifdef __cplusplus } #endif #endif /* LIBSERIALPORT_H */