owcapi − easy C-language 1-wire interface
libowcapi library to link with your program
ssize_t
OW_init( device name or full parameter string
)
ssize_t OW_init_args( int argc, char ** args
)
The full set of initialization options is extensive. They correspond roughly to the command line options of owfs (1) owhttpd (1) and owftpd (1)
int
OW_present( const char * path )
int OW_get( const char * path, char ** buffer, size_t
* buffer_length )
ssize_t OW_lread( const char * path, unsigned char *
buffer, const size_t size, const off_t offset
)
ssize_t
OW_put( const char * path, const char * buffer,
size_t * buffer_length )
ssize_t OW_lwrite( const char * path, const unsigned
char * buffer, const size_t size, const off_t offset
)
void
OW_set_error_level( const char *param )
void OW_set_error_print( const char *param
)
void OW_finish( void )
OW_init_string
offers the full flexibility of the owfs (1) and
owhttpd (1) command line.
Arguments
Can be as simple as jus the device name, a full parameter specification. One or more device names (includes tcp, serial, usb...) and command line switches. See owfs (1) for full syntax.
Returns
0 for success. −1 on error and errno will be set. OW_finish does not need to be called if OW_init fails.
Sequence
One of the init functions must be called before accessing the 1-wire bus. OW_finish is optional.
OW_init_args
offers the full flexibility of the owfs (1) and
owhttpd (1) command line.
Arguments
One or more device names (includes tcp, serial, usb...) and command line switches. See owfs (1) for full syntax. Unlike OW_init_string the arguments are in argv/argc format.
Returns
0 for success. −1 on error and errno will be set. OW_finish does not need to be called if OW_init fails.
Sequence
One of the init functions must be called before accessing the 1-wire bus. OW_finish is optional.
OW_present
is used to check presence of a 1-wire device.
Arguments
path is the path to the directory or file (property).
Returns
0 on success. −1 on error (and errno is set).
Sequence
One of the init functions must be called before accessing the 1-wire bus. OW_finish is optional.
OW_get is
used to get directory listings and file contents. The
results are put in a dynamically allocated buffer.
Arguments
path is the path to the directory or file (property). *buffer returns a pointer to a buffer containing the directory (comma separated) or value. buffer_length returns the length of the value/string in buffer
Returns
number of bytes on success. −1 on error (and errno is set).
Sequence
One of the init functions must be called before accessing the 1-wire bus. OW_finish is optional.
Important note
buffer is allocated ( with malloc ) by OW_get but must be freed in your program. See malloc (3) and free (3)
OW_lread
is used to read 1-wire memory chips. Think of it as a
combination of lseek and read It allows
random-access to the memory, specifying location and length.
Unlike OW_get directories cannot be obtained and the
buffer must be pre-allocated rather than allocated by the
routine. buffer must be at least size length.
Arguments
path is the path to the file (property). buffer is the (pre-allocated) memory area where the value will be placed. size is the length of bytes requested. offset is the position in file to start reading.
Returns
number of bytes on success. −1 on error (and errno is set).
Sequence
One of the init functions must be called before accessing the 1-wire bus. OW_finish is optional.
OW_put is
an easy way to write to 1-wire chips.
Arguments
path is the path to the file (property). buffer is the value to be written. buffer_length is the length of the value buffer. Returns number of bytes on success. −1 on error (and errno is set).
Sequence
One of the init functions must be called before accessing the 1-wire bus. OW_finish is optional.
OW_lwrite
is the companion of OW_lread. It allows writing to
arbitrary positions in 1-wire memory. Think of it as a
combination of lseek and write. buffer must be
at least size length.
Arguments
path is the path to the file (property). buffer is the data to be written. size is the length of bytes to be written. offset is the position in file to start writing.
Returns
number of bytes on success. −1 on error (and errno is set).
Sequence
One of the init functions must be called before accessing the 1-wire bus. OW_finish is optional.
OW_set_error_level
sets the debug output to a certain level. 0 is default, and
higher value gives more output.
(0=default, 1=err_connect, 2=err_call, 3=err_data,
4=err_detail, 5=err_debug, 6=err_beyond)
Arguments
params is the level. Should be an integer.
Returns
None
Sequence
One of the init functions must be called before setting the level, since init defaults to level 0.
OW_set_error_print
sets where the debug output should be directed. 0=mixed
output, 1=syslog, 2=console.
Arguments
params is the level. Should be an integer between 0 and 2.
Returns
None
Sequence
One of the init functions must be called before setting the level, since init defaults to 0 (mixed output).
OW_finish
cleans up the OWFS 1-wire routines, releases devices
and memory.
Arguments
None.
Returns
None
Sequence
OW_finish is optional since cleanup is automatic on program exit.
libowcapi (1) is an encapsulation of the full libow library for C programs.
libowcapi (1) allows a C program to use OWFS principles (consistent naming scheme, multiple adapters, devices, and compatibility) directly from a C program. There are analogous modules for other programming languages:
C |
libowcapi |
|||
perl |
owperl |
|||
php |
owphp |
|||
python |
owpython |
|||
tcl |
owtcl |
/* Simple
directory listing -- no error checking */
#include <owcapi.h>
unsigned char * buf;
size_t s ;
OW_init("/dev/ttyS0");
OW_set_error_print("2");
OW_set_error_level("6");
OW_get("/",&buf,&s) ;
printf("Directory %s0,buf);
free(buf);
OW_finish() ;
http://www.owfs.org
Paul Alfille ([email protected])