mirror of
git://sigrok.org/libserialport
synced 2023-08-10 21:13:24 +03:00
Add documentation.
This commit is contained in:
Martin Ling
Uwe Hermann
parent
e8ffaee986
commit
0a16d4def9
204
README
204
README
@ -0,0 +1,204 @@
|
||||
----------------------------------------------------------------
|
||||
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 an open
|
||||
port. This structure should be allocated by the user and is populated by
|
||||
sp_open(). It can be freed safely after sp_close().
|
||||
|
||||
All functions can return only two possible error values. SP_ERR_ARG indicates
|
||||
the function was called with invalid arguments. SP_ERR_FAIL indicates that the
|
||||
OS reported a failure. Both 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.
|
||||
|
||||
Functions 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
|
||||
-----------
|
||||
|
||||
char **sp_list_ports();
|
||||
|
||||
Lists the serial ports available on the system. The value returned is an array
|
||||
of port names as C strings, terminated by a NULL. It should be freed after use
|
||||
by calling sp_free_port_list().
|
||||
|
||||
void sp_free_port_list(char **list);
|
||||
|
||||
Frees the data structure returned by sp_list_ports().
|
||||
|
||||
Opening and closing ports
|
||||
-------------------------
|
||||
|
||||
int sp_open(struct sp_port *port, char *portname, int flags);
|
||||
|
||||
Opens the specified serial port.
|
||||
|
||||
Parameters:
|
||||
|
||||
port: Pointer to empty port structure, allocated by caller.
|
||||
portname: Name of port to open.
|
||||
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, or SP_ERR_ARG
|
||||
if an invalid port or name 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_params(struct sp_port *port, int baudrate,
|
||||
int bits, int parity, int stopbits,
|
||||
int flowcontrol, int rts, int dtr);
|
||||
|
||||
Sets serial parameters for the specified serial port.
|
||||
|
||||
Parameters:
|
||||
|
||||
port: Pointer to port structure.
|
||||
baudrate: Baud rate to set.
|
||||
bits: Number of data bits to use.
|
||||
parity: Parity setting to use
|
||||
(SP_PARITY_NONE, SP_PARITY_EVEN or SP_PARITY_ODD)
|
||||
stopbits: Number of stop bits to use (1 or 2).
|
||||
flowcontrol: Flow control setting to use
|
||||
(SP_FLOW_NONE, SP_FLOW_HARDWARE or SP_FLOW_SOFTWARE)
|
||||
|
||||
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 a number of bytes from the specified serial port.
|
||||
|
||||
Parameters:
|
||||
|
||||
port: Pointer to port structure.
|
||||
buf: Buffer in which to store the bytes read.
|
||||
count: 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)
|
||||
|
||||
Writes a number of bytes to the specified serial port.
|
||||
|
||||
Parameters:
|
||||
|
||||
port: Pointer to port structure.
|
||||
buf: Buffer containing the bytes to write.
|
||||
count: 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().
|
||||
Loading…
Reference in New Issue
Block a user