+-------------------------------------------------------------------------------
+libserialport: cross-platform library for accessing serial ports
+-------------------------------------------------------------------------------
+
+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:
+
+- Port enumeration (obtaining a list of serial ports on the system).
+- Opening and closing ports.
+- Setting port parameters (baud rate, parity, etc).
+- Reading, writing and flushing data.
+- Obtaining error information.
+
+libserialport is an open source project released under the LGPL3+ license.
+
+Status
+======
+
+The library should build and work on any Windows or Unix-based system. If it
+does not, please submit a bug.
+
+Enumeration is currently only implemented on Windows, Mac OS X and Linux. On
+other systems enumeration will return no results, but ports can still be opened
+by name and then used.
+
+If you know how to enumerate available ports on another OS, please submit a bug
+with this information, or better still a patch implementing it.
+
+Future
+======
+
+Future versions will add additional API calls for obtaining metadata about a
+port, e.g. for USB devices the USB VID and PID of the underlying device.
+
+Dependencies
+============
+
+On Linux, libudev is required. On other systems no other libraries are required.
+
+The libudev dependency could be eliminated in favour of direct sysfs queries at
+the cost of some brevity. This is not currently a priority but if you feel like
+doing this feel free to submit a patch.
+
+Building
+========
+
+The package uses a GNU style build system and requires a Unix style shell.
+On Windows it can be built with the MinGW toolchain and MSYS environment.
+
+Run "./autogen.sh" to generate the build system, "./configure" to setup, then
+"make" to build the library and "make install" to install it.
+
+API
+===
+
+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 'Enumeration' section below.
+
+All functions can return only three possible error values. SP_ERR_ARG indicates
+the function was called with invalid arguments. SP_ERR_FAIL indicates that the
+OS reported a failure. SP_ERR_MEM indicates that a memory allocation failed.
+All of these error values are negative.
+
+When 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 SP_OK, which is equal to zero, or where
+otherwise documented a positive value.
+
+The available functions are as follows:
+
+Enumeration
+-----------
+
+int sp_get_port_by_name(const char *portname, struct sp_port **port_ptr);
+
+ Obtains 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().
+
+ Returns: 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.
+
+void sp_free_port(struct sp_port *port);
+
+ Frees a port structure obtained from sp_get_port_by_name().
+
+int sp_list_ports(struct sp_port ***list_ptr);
+
+ Lists 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().
+
+ Returns: 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.
+
+int sp_copy_port(const struct sp_port *port, struct sp_port **copy_ptr);
+
+ Makes 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().
+
+ Returns: 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.
+
+void sp_free_port_list(struct sp_port **list);
+
+ Frees 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().
+
+Opening and closing ports
+-------------------------
+
+int sp_open(struct sp_port *port, int flags);
+
+ Opens the specified serial port.
+
+ Parameters:
+
+ port: Pointer to port structure.
+ flags: Flags to use when opening the serial port. Possible
+ flags are: SP_MODE_RDWR, SP_MODE_RDONLY, and SP_MODE_NONBLOCK.
+
+ Returns: 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.
+
+int sp_close(struct sp_port *port);
+
+ Closes the specified serial port.
+
+ Returns: SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
+ if an invalid port is passed.
+
+Setting port parameters
+-----------------------
+
+int sp_set_baudrate(struct sp_port *port, int baudrate)
+
+ Sets the baud rate for the specified serial port.
+
+ Parameters:
+
+ port: Pointer to port structure.
+ baud: Baud rate in bits per second.
+
+ Returns: SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
+ for invalid arguments.
+
+int sp_set_bits(struct sp_port *port, int bits)
+
+ Sets the number of data bits for the specified serial port.
+
+ Parameters:
+
+ port: Pointer to port structure.
+ bits: Number of data bits to use. Valid values are 5 to 8.
+
+ Returns: SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
+ for invalid arguments.
+
+int sp_set_parity(struct sp_port *port, int parity)
+
+ Sets the parity for the specified serial port.
+
+ Parameters:
+
+ port: Pointer to port structure.
+ parity: Parity setting to use.
+ (SP_PARITY_NONE, SP_PARITY_EVEN or SP_PARITY_ODD)
+
+ Returns: SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
+ for invalid arguments.
+
+int sp_set_stopbits(struct sp_port *port, int stopbits)
+
+ Sets the number of stop bits for the specified port.
+
+ Parameters:
+
+ port: Pointer to port structure.
+ stopbits: Number of stop bits to use (1 or 2).
+
+ Returns: SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
+ for invalid arguments.
+
+int sp_set_flowcontrol(struct sp_port *port, int flowcontrol)
+
+ Sets 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.
+
+ Parameters:
+
+ port: Pointer to port structure.
+ flowcontrol: Flow control setting to use. Valid settings are:
+
+ SP_FLOWCONTROL_NONE: No flow control.
+ SP_FLOWCONTROL_XONXOFF: Software flow control using XON/XOFF characters.
+ SP_FLOWCONTROL_RTSCTS: Hardware flow control using RTS/CTS signals.
+ SP_FLOWCONTROL_DTRDSR: Hardware flow control using DTR/DSR signals.
+
+ Returns: SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
+ for invalid arguments.
+
+int sp_set_config(struct sp_port *port, struct sp_port_config *config)
+
+ Sets all parameters for the specified serial port.
+
+ The user should populate a struct sp_port_config, then pass a pointer to it
+ as the config parameter.
+
+ The fields of sp_port_config are:
+
+ int baudrate: Baud rate in bits per second.
+ int bits: Number of data bits to use. Valid values are 5 to 8.
+ int parity: Parity setting to use.
+ (SP_PARITY_NONE, SP_PARITY_EVEN or SP_PARITY_ODD)
+ int stopbits: Number of stop bits to use (1 or 2).
+ int rts: RTS pin mode.
+ (SP_RTS_ON, SP_RTS_OFF or SP_RTS_FLOW_CONTROL)
+ int cts: CTS pin mode.
+ (SP_CTS_IGNORE or SP_CTS_FLOW_CONTROL)
+ int dtr: DTR pin mode.
+ (SP_DTR_ON, SP_DTR_OFF or SP_DTR_FLOW_CONTROL)
+ int dsr: DSR pin mode.
+ (SP_DSR_IGNORE or SP_DSR_FLOW_CONTROL)
+ int xon_xoff: XON/XOFF flow control mode.
+ (SP_XONXOFF_DISABLED, SP_XONXOFF_IN,
+ SP_XONXOFF_OUT or SP_XONXOFF_INOUT)
+
+ To retain the current value of any setting, set the field to to a
+ negative value.
+
+ Returns: SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
+ for invalid arguments.
+
+Reading, writing and flushing data
+----------------------------------
+
+int sp_read(struct sp_port *port, const void *buf, size_t count)
+
+ Reads 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.
+
+ Parameters:
+
+ port: Pointer to port structure.
+ buf: Buffer in which to store the bytes read.
+ count: Maximum number of bytes to read.
+
+ Returns: The number of bytes read, SP_ERR_FAIL on failure,
+ or SP_ERR_ARG for invalid arguments.
+
+int sp_write(struct sp_port *port, const 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.
+
+ Parameters:
+
+ port: Pointer to port structure.
+ buf: Buffer containing the bytes to write.
+ count: Maximum number of bytes to write.
+
+ Returns: The number of bytes written, SP_ERR_FAIL on failure,
+ or SP_ERR_ARG for invalid arguments.
+
+int sp_flush(struct sp_port *port);
+
+ Flushes serial port buffers.
+
+ Returns: SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
+ if an invalid port is passed.
+
+Error handling
+--------------
+
+int sp_last_error_code();
+
+ Gets 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.
+
+ Returns: The system's numeric code for the error that caused the last
+ operation to fail.
+
+char *sp_last_error_message();
+
+ Gets the error message for failed operation.
+
+ In order to obtain the correct result, this function should be called
+ straight after the failure, before executing other system operations.
+
+ Returns: 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.
+
+void sp_free_error_message(char *message);
+
+ Frees the error message returned by sp_last_error_message().
projects / libserialport.git / blobdiff