diff options
Diffstat (limited to 'doc/info/mds.texinfo')
| -rw-r--r-- | doc/info/mds.texinfo | 67 |
1 files changed, 64 insertions, 3 deletions
diff --git a/doc/info/mds.texinfo b/doc/info/mds.texinfo index 12cde09..b54e10e 100644 --- a/doc/info/mds.texinfo +++ b/doc/info/mds.texinfo @@ -714,6 +714,7 @@ were closed the last time they were closed. * Filesystem:: The display server's footprint on the filesystem. * Message Passing:: Sending messages between servers and clients. * Interception:: Implementing protocols and writing unanticipated clients. +* Responses:: How responses to queries and commands are structured. * Portability:: Restrictions for portability on protocols. @end menu @@ -1245,6 +1246,62 @@ Command: keyboard-enumeration\n +@node Responses +@section Responses + +@cpindex Responses +@cpindex Error management +Many commands are met with no response. The client, +can however sometimes infer when the commands has +been processed by listening for events that are +triggered when some commands have been process. +Other times, commands are responded to with an +error message either indicating success or failure. +@footnote{See @ref{error}}. + +Queries are always met with a response unless +the an involved server failed or the queries was +malformated or included invalid parameters and +therefore silently@footnote{Although in these +cases most servers will print an error to their +stderr} ignored. The response will either be +an error message indicating failure (or success +in very special cases,) or an especially formatted +message that includes describes the requested data. + +Responses will always include at least four headers: +@table @code +@item To +Will include the client's, who made the request, +client ID. This will be the value of the header +@code{Client ID} in the message that triggered +the response. + +@item In response to +Will include the message ID of the message that +triggered the response. The value of the +@code{Message ID}-header of the received message. + +@item Message ID +The ID of the response message. You will probably +not find any use of this. But it is required by +the message passing protocol. + +@item Origin command +The value of this header will be the value of the +@code{Command}-header in the received message. +This can be used if you want to listen for +responses, and perhaps modify them, between +other servers and clients. +@end table + +The message @code{Command: assign-id} is except from +this sections. In particular it will not include the +headers @code{To}, @code{Message ID} and +@code{Origin command}. See @ref{Message Passing}. + + + @node Portability @section Portability @@ -3129,6 +3186,7 @@ do not implement this in your server. @prindex @code{error} @cpindex Error management +@cpindex Responses @table @asis @item Identifying header: @code{Command: error} @@ -4313,7 +4371,7 @@ reference implementation will pop entries that have timed out when a new entry is added, the reading on the clipstack is requested or the server is reexecuted, but another implement may choose to pop -entires asynchronously using another thread or an +entries asynchronously using another thread or an alarm an pop when @code{SIGALRM} is received. Available and optional if the @code{Action: add} is @@ -4350,7 +4408,7 @@ Optional. @item Action: The clipboard server sends out some information about what it is doing, such as automatically removing -entires. +entries. @item Included header: @code{Event} @table @code @@ -6901,7 +6959,7 @@ to terminated the string, but @code{192 128} is not.} This function returns zero if the @code{string} is properly formatted, and @code{-1} otherwise. -@item @code{construct_error_message} [(@code{const char* restrict recv_client_id, const char* restrict recv_message_id, int custom, int errnum, const char* restrict message, char** restrict send_buffer, size_t* restrict send_buffer_size, uint32_t message_id}) @arrow{} @code{size_t}] +@item @code{construct_error_message} [(@code{const char* restrict recv_client_id, const char* restrict recv_message_id, const char* restrict recv_command, int custom, int errnum, const char* restrict message, char** restrict send_buffer, size_t* restrict send_buffer_size, uint32_t message_id}) @arrow{} @code{size_t}] @cpindex @code{construct_error_message} @cpindex Error management This function constructs an error message to be sent to @@ -6923,6 +6981,9 @@ that is, the value of the header @code{Message ID} on the received message and the header @code{In response to} in the message to construct. Must not be @code{NULL}. +@item recv_command +The value of the @code{Command}-header on the +message that was received. Must not be @code{NULL}. @item custom If and only if set to zero, value of @code{errnum} is a value for @code{errno}. |