-----------------------------------------------------------------
+-------------------------------------------------------------------------------
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.
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 serial
-port. This structure is obtained from the array returned by sp_list_ports().
+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
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
+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:
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 value pointed to by port_ptr will be set to NULL.
+ 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);
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().
+ 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);
- 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 value pointed to by list_ptr will be set to NULL.
+ 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().
+ 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
-------------------------
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 is passed.
+ 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);
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);
+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 serial parameters for the specified serial port.
+ 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.
- 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)
+ 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.
projects / libserialport.git / blobdiff