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Queuer-Searcher Communications

@everyfooting Author: ensley // Editor: ensley // Texinfo: ensley @| @| 3 December 1994

General Overview

When the Searcher is ready for a search, it signals the Queuer using SIGUSR1. If their is anything in the queue, the Queuer sends the search request "packet" down the pipe to the standard in of the Searcher. Remember the Queuer originally spawned the Searcher process using popen() library call. The definition of this "packet" shall be kept in the common includes directory INSTALLDIR/server/src/include/ and is called queuer-searcher.h. If any modifications are needed for future versions of Free Arhcie, this should make things easier. Ideally functions that deal with this pipe and the packet directly should be kept in a separate file.

The Searcher does not have to signal the Queuer for the first request. It is assumed that the Searcher is initially waiting and willing to take a search request.

The current data packet looks like this:

• Type of search
• Number of maximum hits
• Search string
• Unique ID

Let's look at the data packet in more detail.

• Type of Search - Integer
  The current search types are:
  • 2 - EXACT
  • 3 - SUBCASE
  • 4 - SUBSTRING
  • 5 - REGEXP

  These are defined in ~server/src/include/search-types.h. This file should be included in all interfaces and queuer source. All types will be referred in the source code as EXACT, SUBCASE, SUBSTRING, and REGEXP.

• Number of maximum hits - Integer Range 0-1000 Default: 100

• Search String - String (null terminating)

• Unique ID - String (null terminating) Holds the interface's process ID and the search number. It has the form "pid.number"

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