Volume 7A: XView Programming Manual

Example A-3. The long_seln.c program (continued)

{

char *text = get_selection();

if (text)

printf("–––seln–––\n%.*s [...]\n–––end seln–––\n", 20, text);

}

/*

* return the text selected in the current selection rank. Use

* selection_query() to guarantee that the entire selection is

* retrieved. selection_query() calls our installed routine,

* read_proc() (see below).

*/

char *

get_selection()

{

Seln_holder holder;

Seln_result result;

Seln_request *response;

char context = FIRST_BUFFER;

holder = selection_inquire(server, seln_type);

printf("selection type = %s\n",

seln_type == SELN_PRIMARY? "primary" :

seln_type == SELN_SECONDARY? "secondary" : "shelf");

/* result is based on the return value of read_proc() */

result = selection_query(server, &holder, read_proc, &context,

SELN_REQ_BYTESIZE, NULL,

SELN_REQ_CONTENTS_ASCII, NULL,

NULL);

if (result == SELN_FAILED) {

puts("couldn’t get selection");

return NULL;

}

return seln_bufs[seln_type ];

}

/*

* Called by selection_query for every buffer of information received.

* Short messages (under about 2000 bytes) will fit into one buffer.

* For larger messages, read_proc is called for each buffer in the

* selection. The context pointer passed to selection_query is

* modified by read_proc so that we know if this is the first buffer

* or not.

*/

Seln_result

read_proc(response)

Seln_request *response;

{

char *reply; /* pointer to the data in the response received */

long seln_len; /* total number of bytes in the selection */

static long seln_have_bytes;

/* number of bytes of the selection

* which have been read; cumulative over all calls for

650 XView Programming Manual

Example A-3. The long_seln.c program (continued)

* the same selection (it is reset when the first

* response of a selection is read)

*/

printf("read_proc status: %s (%d)\n",

response->status == SELN_FAILED? "failed" :

response->status == SELN_SUCCESS? "succeeded" :

response->status == SELN_CONTINUED? "continued" : "???",

response->status);

if (*response->requester.context == FIRST_BUFFER) {

reply = response->data;

/* read in the length of the selection -- first attribute.

* advance "reply" passed attribute to point to actual data.

*/

reply += sizeof(SELN_REQ_BYTESIZE);

/* set seln_len to actual data now. (bytes selected) */

seln_len = *(int *)reply;

printf("selection size is %ld bytes\n", seln_len);

/* advance "reply" to next attribute in list */

reply += sizeof(long);

/* create a buffer large enough to store entire selection */

if (seln_bufs[seln_type] != NULL)

free(seln_bufs[seln_type ]);

if (!(seln_bufs[seln_type] = malloc(seln_len + 1))) {

puts("out of memory");

return(SELN_FAILED);

}

seln_have_bytes = 0;

/* move "reply" passed attribute so it points to contents */

reply += sizeof(SELN_REQ_CONTENTS_ASCII);

*response->requester.context = NOT_FIRST_BUFFER;

} else {

/* this is not the first buffer, so the contents of the

* response is just more of the selection

*/

reply = response->data;

}

/* copy data from received to the seln buffer allocated above */

(void) strcpy(&seln_bufs[seln_type ][seln_have_bytes], reply);

seln_have_bytes += strlen(reply);

return SELN_SUCCESS;

}

The Selection

Service

The Selection Service 651

A.5 Selection Package Summary

Table A-2 lists the procedures and macros in the Selection Service. Table A-3 lists the

Selection Service Attributes.

Table A-2. Selection Service Procedures

Selection Procedures

selection_acquire() selection_inform()

selection_ask() selection_init_request()

selection_clear_functions() selection_inquire()

selection_create() selection_inquire_all()

selection_destroy() selection_query()

selection_done() selection_report_event()

selection_figure_response() selection_request()

selection_hold_file() selection_yield_all()

Table A-3. Selection Service Attributes

Selection Attributes Advanced Selection Attributes

SELN_REQ_BYTESIZE SELN_REQ_COMMIT_PENDING_DELETE

SELN_REQ_CONTENTS_ASCII SELN_REQ_CONTENTS_PIECES

SELN_REQ_DELETE SELN_REQ_FAKE_LEVEL

SELN_REQ_END_REQUEST SELN_REQ_FIRST

SELN_REQ_FILE_NAME SELN_REQ_FIRST_UNIT

SELN_REQ_YIELD SELN_REQ_LAST

SELN_REQ_LAST_UNIT

SELN_REQ_LEVEL

SELN_REQ_RESTORE

SELN_REQ_SET_LEVEL

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