79 lines
3.0 KiB
Plaintext
79 lines
3.0 KiB
Plaintext
UPSCLIENT(3)
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============
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NAME
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----
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upsclient - Network UPS Tools client access library
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DESCRIPTION
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-----------
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The Network UPS Tools (NUT) *upsclient* library provides a number of
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useful functions for programs to use when communicating with
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linkman:upsd[8]. Many of the low-level socket and protocol details are
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handled automatically when using this interface.
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State is maintained across calls in an opaque structure called `UPSCONN_t`.
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Callers are expected to create one per connection. These will be
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provided to most of the *upsclient* functions. The format of this
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structure is subject to change, and client programs must not reference
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elements within it directly.
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INITIALIZATION AND CLEANUP
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--------------------------
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Before creating any connection, and in general using any upscli function,
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you must call linkman:upscli_init[3] with proper parameters to initialize
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upscli module.
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To register specific host security policy, you must call
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linkman:upscli_add_host_cert[3] before initialize connection to it.
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In the same way, just before exiting, and after all upscli usage, you must
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call linkman:upscli_cleanup[3] to flush cache files and perform other cleanup.
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NETWORK FUNCTIONS
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-----------------
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To create a new connection, use linkman:upscli_connect[3]. This will also
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initialize the `UPSCONN_t` structure. To verify that a connection has been
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established later, linkman:upscli_fd[3] can be used to return the
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file descriptor. Clients wishing to check for the presence and
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operation of SSL on a connection may call linkman:upscli_ssl[3].
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The majority of clients will use linkman:upscli_get[3] to retrieve single
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items from the server. To retrieve a list, use
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linkman:upscli_list_start[3] to get it started, then call
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linkman:upscli_list_next[3] for each element.
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Raw lines of text may be sent to linkman:upsd[8] with
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linkman:upscli_sendline[3]. Reading raw lines is possible with
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linkman:upscli_readline[3]. Client programs are expected to format these
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lines according to the protocol, as no checking will be performed before
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transmission.
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At the end of a connection, you must call linkman:upsclient_disconnect[3]
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to disconnect from *upsd* and release any dynamic memory associated
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with the `UPSCONN_t` structure. Failure to call this function will result
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in memory and file descriptor leaks in your program.
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ERROR HANDLING
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--------------
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In the event of an error, linkman:upscli_strerror[3] will provide
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human-readable details on what happened. linkman:upscli_upserror[3] may
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also be used to retrieve the error number. These numbers are defined in
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*upsclient.h* as 'UPSCLI_ERR_*'.
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SEE ALSO
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--------
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linkman:libupsclient-config[1],
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linkman:upscli_init[3], linkman:upscli_cleanup[3], linkman:upscli_add_host_cert[3],
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linkman:upscli_connect[3], linkman:upscli_disconnect[3], linkman:upscli_fd[3],
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linkman:upscli_getvar[3], linkman:upscli_list_next[3],
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linkman:upscli_list_start[3], linkman:upscli_readline[3],
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linkman:upscli_sendline[3],
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linkman:upscli_splitaddr[3], linkman:upscli_splitname[3],
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linkman:upscli_ssl[3], linkman:upscli_strerror[3],
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linkman:upscli_upserror[3]
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