.\"	$Id: mansearch.3,v 1.5 2017/03/30 22:22:05 schwarze Exp $
.\"
.\" Copyright (c) 2014 Ingo Schwarze <schwarze@openbsd.org>
.\"
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.Dd $Mdocdate: March 30 2017 $
.Dt MANSEARCH 3
.Os
.Sh NAME
.Nm mansearch
.Nd search manual page databases
.Sh SYNOPSIS
.In stdint.h
.In manconf.h
.In mansearch.h
.Ft int
.Fo mansearch
.Fa "const struct mansearch *search"
.Fa "const struct manpaths *paths"
.Fa "int argc"
.Fa "char *argv[]"
.Fa "struct manpage **res"
.Fa "size_t *sz"
.Fc
.Sh DESCRIPTION
The
.Fn mansearch
function returns information about manuals matching a search query from a
.Xr mandoc.db 5
database.
.Pp
The query arguments are as follows:
.Bl -tag -width Ds
.It Fa "const struct mansearch *search"
Search options, defined in
.In mansearch.h .
.It Fa "const struct manpaths *paths"
Directories to be searched, defined in
.In manconf.h .
.It Fa "int argc" , "char *argv[]"
Search criteria, usually taken from the command line.
.El
.Pp
The output arguments are as follows:
.Bl -tag -width Ds
.It Fa "struct manpage **res"
Returns a pointer to an array of result structures defined in
.In mansearch.h .
The user is expected to call
.Xr free 3
on the
.Va file ,
.Va names ,
and
.Va output
fields of all structures, as well as the
.Fa res
array itself.
.It Fa "size_t *sz"
Returns the number of result structures contained in
.Fa res .
.El
.Sh IMPLEMENTATION NOTES
For each manual page tree, the search is done in two steps.
In the first step, a list of pages matching the search criteria is built.
In the second step, the requested information about these pages is
retrieved from the database and assembled into the
.Fa res
array.
.Pp
All function mentioned here are defined in the file
.Pa mansearch.c .
.Ss Finding matches
Command line parsing is done by the function
.Fn exprcomp
building a singly linked list of
.Vt expr
structures, using the helper functions
.Fn expr_and
and
.Fn exprterm .
.Ss Assembling the results
The names, sections, and architectures of the manuals found
are assembled into the
.Va names
field of the result structure by the function
.Fn buildnames .
.Sh FILES
.Bl -tag -width mandoc.db -compact
.It Pa mandoc.db
The manual page database.
.El
.Sh SEE ALSO
.Xr apropos 1 ,
.Xr mandoc.db 5 ,
.Xr makewhatis 8
.Sh HISTORY
The
.Fn mansearch
subsystem first appeared in
.Ox 5.6 .
.Sh AUTHORS
.An -nosplit
A module to search manual page databases was first written by
.An Kristaps Dzonsons Aq Mt kristaps@bsd.lv
in 2011, at first using the Berkeley DB;
he rewrote it for SQLite3 in 2012, and
.An Ingo Schwarze Aq Mt schwarze@openbsd.org
removed the dependency on SQLite3 in 2016.