InfoMagic Source Code 1993 July/THE_SOURCE_CODE_CD_ROM.iso/X/mit/doc/Xlib/CH15

Text File | 1991-08-27 | 49.5 KB | 1,577 lines

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\s+1\fBChapter 15\fP\s-1

\s+1\fBResource Manager Functions\fP\s-1
.sp 2
.nr H1 15
.nr H2 0
.nr H3 0
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.nr H5 0
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.LP
.XS
Chapter 15: Resource Manager Functions
.XE
A program often needs a variety of options in the X environment
(for example, fonts, colors, icons, and cursors).
Specifying all of these options on the command line is awkward
because users may want to customize many aspects of the program
and need a convenient way to establish these customizations as
the default setting.
The resource manager is provided for this purpose.
Resource specifications are usually stored in human-readable files
and in server properties.
.LP
The resource manager is a database manager with a twist.
In most database systems,
you perform a query using an imprecise specification,
and you get back a set of records.
The resource manager, however, allows you to specify a large
set of values with an imprecise specification, to query the database
with a precise specification, and to get back only a single value.
This should be used by applications that need to know what the
user prefers for colors, fonts, and other resources.
It is this use as a database for dealing with X resources that
inspired the name ``Resource Manager,''
although the resource manager can be and is used in other ways.
.LP
For example,
a user of your application may want to specify
that all windows should have a blue background
but that all mail-reading windows should have a red background.
With well-engineered and coordinated applications,
a user can define this information using only two lines of specifications.
.LP
As an example of how the resource manager works,
consider a mail-reading application called xmh.
Assume that it is designed so that it uses a
complex window hierarchy all the way down to individual command buttons,
which may be actual small subwindows in some toolkits.
These are often called objects or widgets.
In such toolkit systems,
each user interface object can be composed of other objects
and can be assigned a name and a class.
Fully qualified names or classes can have arbitrary numbers of component names,
but a fully qualified name always has the same number of component names as a
fully qualified class.
This generally reflects the structure of the application as composed
of these objects, starting with the application itself.
.LP
For example, the xmh mail program has a name ``xmh'' and is one
of a class of ``Mail'' programs.
By convention, the first character of class components is capitalized,
and the first letter of name components is in lowercase.
Each name and class finally has an attribute
(for example ``foreground'' or ``font'').
If each window is properly assigned a name and class,
it is easy for the user to specify attributes of any portion
of the application.
.LP
At the top level,
the application might consist of a paned window (that is, a window divided
into several sections) named ``toc''.
One pane of the paned window is a button box window named ``buttons''
and is filled with command buttons.
One of these command buttons is used to incorporate
new mail and has the name ``incorporate''.
This window has a fully qualified name, ``xmh.toc.buttons.incorporate'',
and a fully qualified class, ``Xmh.Paned.Box.Command''.
Its fully qualified name is the name of its parent, ``xmh.toc.buttons'',
followed by its name, ``incorporate''.
Its class is the class of its parent, ``Xmh.Paned.Box'',
followed by its particular class, ``Command''.
The fully qualified name of a resource is
the attribute's name appended to the object's fully qualified
name, and the fully qualified class is its class appended to the object's
class.
.LP
The incorporate button might need the following resources:
Title string,
Font,
Foreground color for its inactive state,
Background color for its inactive state,
Foreground color for its active state, and
Background color for its active state.
Each resource is considered
to be an attribute of the button and, as such, has a name and a class.
For example, the foreground color for the button in
its active state might be named ``activeForeground'',
and its class might be ``Foreground''.
.LP
When an application looks up a resource (for example, a color),
it passes the complete name and complete class of the resource
to a lookup routine.
The resource manager compares this complete specification
against the incomplete specifications of entries in the resource
database, find the best match, and returns the corresponding
value for that entry.
.LP
The definitions for the resource manager are contained in
.Pn < X11/Xresource.h >.
.NH 2
Resource File Syntax
.XS
\*(SN Resource File Syntax
.XE
.LP
The syntax of a resource file is a sequence of resource lines
terminated by newline characters or end of file.
The syntax of an individual resource line is:
.LP
.\" Start marker code here
.Ds 0
.TA 1.5i 1.75i
.ta 1.5i 1.75i
ResourceLine    =    Comment | IncludeFile | ResourceSpec | <empty line>
Comment    =    "!" {<any character except null or newline>}
IncludeFile    =    "#" WhiteSpace "include" WhiteSpace FileName WhiteSpace
FileName    =    <valid filename for operating system>
ResourceSpec    =    WhiteSpace ResourceName WhiteSpace ":" WhiteSpace Value
ResourceName    =    [Binding] {Component Binding} ComponentName
Binding    =    "\&." | "*"
WhiteSpace    =    {<space> | <horizontal tab>}
Component    =    "?" | ComponentName
ComponentName    =    NameChar {NameChar}
NameChar    =    "a"\-"z" | "A"\-"Z" | "0"\-"9" | "_" | "-"
Value    =    {<any character except null or unescaped newline>}
.De
.\" End marker code here
.LP
Elements separated by vertical bar (|) are alternatives.
Curly braces ({\&.\&.\&.}) indicate zero or more repetitions
of the enclosed elements.
Square brackets ([\&.\&.\&.]) indicate that the enclosed element is optional.
Quotes ("\&.\&.\&.") are used around literal characters.
.LP
IncludeFile lines are interpreted by replacing the line with the
contents of the specified file.  The word "include" must be in lowercase.
The filename is interpreted relative to the directory of the file in
which the line occurs (for example, if the filename contains no
directory or contains a relative directory specification).
.LP
If a ResourceName contains a contiguous sequence of two or more Binding
characters, the sequence will be replaced with single "\&." character
if the sequence contains only "\&." characters,
otherwise the sequence will be replaced with a single "*" character.
.LP
A resource database never contains more than one entry for a given
ResourceName.  If a resource file contains multiple lines with the
same ResourceName, the last line in the file is used.
.LP
Any whitespace character before or after the name or colon in a ResourceSpec
are ignored.
To allow a Value to begin with whitespace,
the two-character sequence ``\\\^\fIspace\fP'' (backslash followed by space)
is recognized and replaced by a space character,
and the two-character sequence ``\\\^\fItab\fP''
(backslash followed by horizontal tab)
is recognized and replaced by a horizontal tab character.
To allow a Value to contain embedded newline characters,
the two-character sequence ``\\\^n'' is recognized and replaced by a
newline character.
To allow a Value to be broken across multiple lines in a text file,
the two-character sequence ``\\\^\fInewline\fP''
(backslash followed by newline) is
recognized and removed from the value.
To allow a Value to contain arbitrary character codes,
the four-character sequence ``\\\^\fInnn\fP'',
where each \fIn\fP is a digit character in the range of ``0''\-``7'',
is recognized and replaced with a single byte that contains
the octal value specified by the sequence.
Finally, the two-character sequence ``\\\\'' is recognized
and replaced with a single backslash.
.LP
As an example of these sequences,
the following resource line contains a value consisting of four
characters: a backslash, a null, a ``z'', and a newline:
.Ds
magic.values: \\\\\\\^000\^\\
z\\\^n
.De
.NH 2
Resource Manager Matching Rules
.XS
\*(SN Resource Manager Matching Rules
.XE
.LP
The algorithm for determining which resource database entry
matches a given query is the heart of the resource manager.
All queries must fully specify the name and class of the desired resource
(use of "*" and "?" are not permitted).
The library supports up to 100 components in a full name or class.
Resources are stored in the database with only partially specified
names and classes, using pattern matching constructs.
An asterisk (*) is a loose binding and is used to represent any number
of intervening components, including none.
A period (.) is a tight binding and is used to separate immediately
adjacent components.
A question mark (?) is used to match any single component name or class.
A database entry cannot end in a loose binding;
the final component (which cannot be "?") must be specified.
The lookup algorithm searches the database for the entry that most
closely matches (is most specific for) the full name and class being queried.
When more than one database entry matches the full name and class,
precedence rules are used to select just one.
.LP
The full name and class are scanned from left to right (from highest
level in the hierarchy to lowest), one component at a time.
At each level, the corresponding component and/or binding of each
matching entry is determined, and these matching components and
bindings are compared according to precedence rules.
Each of the rules is applied at each level,
before moving to the next level,
until a rule selects a single entry over all others.
The rules (in order of precedence) are:
.IP 1. 5
An entry that contains a matching component (whether name, class, or "?")
takes precedence over entries that elide the level (that is, entries
that match the level in a loose binding).
.IP 2. 5
An entry with a matching name takes precedence over both
entries with a matching class and entries that match using "?".
An entry with a matching class takes precedence over
entries that match using "?".
.IP 3. 5
An entry preceded by a tight binding takes precedence over entries
preceded by a loose binding.
.LP
To illustrate these rules, consider following the resource database entries:
.Ds
.TA 2.5i 3.5i
.ta 2.5i 3.5i
xmh*Paned*activeForeground:    red    \fI(entry A)\fP
*incorporate.Foreground:    blue    \fI(entry B)\fP
xmh.toc*Command*activeForeground:    green    \fI(entry C)\fP
xmh.toc*?.Foreground:    white    \fI(entry D)\fP
xmh.toc*Command.activeForeground:    black    \fI(entry E)\fP
.De
.LP
Consider a query for the resource:
.LP
.Ds
.TA 3.5i
.ta 3.5i
xmh.toc.messagefunctions.incorporate.activeForeground    \fI(name)\fP
Xmh.Paned.Box.Command.Foreground    \fI(class)\fP
.De
.LP
At the first level (xmh, Xmh) rule 1 eliminates entry B.
At the second level (toc, Paned) rule 2 eliminates entry A.
At the third level (messagefunctions, Box) no entries are eliminated.
At the fourth level (incorporate, Command) rule 2 eliminates entry D.
At the fifth level (activeForeground, Foreground) rule 3 eliminates entry C.
.NH 2
Quarks
.XS
\*(SN Quarks
.XE
.LP
Most uses of the resource manager involve defining names,
classes, and representation types as string constants.
However, always referring to strings in the resource manager can be slow,
because it is so heavily used in some toolkits.
To solve this problem,
a shorthand for a string is used in place of the string
in many of the resource manager functions.
Simple comparisons can be performed rather than string comparisons.
The shorthand name for a string is called a quark and is the
type
.PN XrmQuark .
On some occasions,
you may want to allocate a quark that has no string equivalent.
.LP
A quark is to a string what an atom is to a string in the server,
but its use is entirely local to your application.
.LP
.sp
To allocate a new quark, use
.PN XrmUniqueQuark .
.IN "XrmUniqueQuark" "" "@DEF@"
.\" Start marker code here
.FD 0
XrmQuark XrmUniqueQuark\^(\|)
.FN
.\" End marker code here
.LP
The
.PN XrmUniqueQuark
function allocates a quark that is guaranteed not to represent any string that
is known to the resource manager.
.LP
.sp
Each name, class, and representation type is typedef'd as an
.PN XrmQuark .
.LP
.\" Start marker code here
.Ds 0
typedef int XrmQuark, *XrmQuarkList;
typedef XrmQuark XrmName;
typedef XrmQuark XrmClass;
typedef XrmQuark XrmRepresentation;
#define NULLQUARK ((XrmQuark) 0)
.De
.\" End marker code here
.LP
Lists are represented as null-terminated arrays of quarks.
The size of the array must be large enough for the number of components used.
.LP
.\" Start marker code here
.Ds 0
typedef XrmQuarkList XrmNameList;
typedef XrmQuarkList XrmClassList;
.De
.\" End marker code here
.LP
.sp
To convert a string to a quark, use
.PN XrmStringToQuark
or
.PN XrmPermStringToQuark .
.IN "XrmStringToQuark" "" "@DEF@"
.IN "XrmPermStringToQuark" "" "@DEF@"
.\" Start marker code here
.FD 0
#define XrmStringToName(string) XrmStringToQuark(string)
#define XrmStringToClass(string) XrmStringToQuark(string)
#define XrmStringToRepresentation(string) XrmStringToQuark(string)
.sp
XrmQuark XrmStringToQuark\^(\^\fIstring\fP\^)
.br
     char *\fIstring\fP\^;
.sp
XrmQuark XrmPermStringToQuark\^(\^\fIstring\fP\^)
.br
     char *\fIstring\fP\^;
.FN
.ds Ql
.IP \fIstring\fP 1i
Specifies the string for which a quark\*(Ql is to be allocated.
.\" End marker code here
.LP
These functions can be used to convert from string to quark representation.
If the string is not in the Host Portable Character Encoding
the conversion is implementation dependent.
The string argument to
.PN XrmStringToQuark
need not be permanently allocated storage.
.PN XrmPermStringToQuark
is just like
.PN XrmStringToQuark ,
except that Xlib is permitted to assume the string argument is permanently
allocated,
and hence that it can be used as the value to be returned by
.PN XrmQuarkToString .
.LP
.sp
To convert a quark to a string, use
.PN XrmQuarkToString .
.IN "XrmQuarkToString" "" "@DEF@"
.\" Start marker code here
.FD 0
#define XrmNameToString(name) XrmQuarkToString(name)
#define XrmClassToString(class) XrmQuarkToString(class)
#define XrmRepresentationToString(type) XrmQuarkToString(type)
.sp
char *XrmQuarkToString\^(\^\fIquark\fP\^)
.br
     XrmQuark \fIquark\fP\^;
.FN
.IP \fIquark\fP 1i
Specifies the quark for which the equivalent string is desired.
.\" End marker code here
.LP
This function can be used to convert from quark representation to string.
The string pointed to by the return value must not be modified or freed.
The returned string is byte-for-byte equal to the original
string passed to one of the string-to-quark routines.
If no string exists for that quark,
.PN XrmQuarkToString
returns NULL.
For any given quark, if
.PN XrmQuarkToString
returns a non-NULL value,
all future calls will return the same value (identical address).
.LP
.sp
To convert a string with one or more components to a quark list, use
.PN XrmStringToQuarkList .
.IN "XrmStringToQuarkList" "" "@DEF@"
.\" Start marker code here
.FD 0
#define XrmStringToNameList(str, name)  XrmStringToQuarkList((str), (name))
#define XrmStringToClassList(str,class) XrmStringToQuarkList((str), (class))
.sp
void XrmStringToQuarkList\^(\^\fIstring\fP, \fIquarks_return\fP\^)
.br
     char *\fIstring\fP\^;
.br
     XrmQuarkList \fIquarks_return\fP\^;
.FN
.ds Ql \ list
.IP \fIstring\fP 1i
Specifies the string for which a quark\*(Ql is to be allocated.
.IP \fIquarks_return\fP 1i
Returns the list of quarks.
.\" End marker code here
.LP
The
.PN XrmStringToQuarkList
function converts the null-terminated string (generally a fully qualified name)
to a list of quarks.
Note that the string must be in the valid ResourceName format
(see section 15.1).
If the string is not in the Host Portable Character Encoding
the conversion is implementation dependent.
.LP
A binding list is a list of type
.PN XrmBindingList
and indicates if components of name or class lists are bound tightly or loosely
(that is, if wildcarding of intermediate components is specified).
.LP
.Ds 0
typedef enum {XrmBindTightly, XrmBindLoosely} XrmBinding, *XrmBindingList;
.De
.LP
.PN XrmBindTightly
indicates that a period separates the components, and
.PN XrmBindLoosely
indicates that an asterisk separates the components.
.LP
.sp
To convert a string with one or more components to a binding list
and a quark list, use
.PN XrmStringToBindingQuarkList .
.IN "XrmStringToBindingQuarkList" "" "@DEF@"
.\" Start marker code here
.FD 0
XrmStringToBindingQuarkList\^(\^\fIstring\fP, \fIbindings_return\fP, \
\fIquarks_return\fP\^)
.br
     char *\fIstring\fP\^;
.br
     XrmBindingList \fIbindings_return\fP\^;
.br
     XrmQuarkList \fIquarks_return\fP\^;
.FN
.ds Ql \ list
.IP \fIstring\fP 1i
Specifies the string for which a quark\*(Ql is to be allocated.
.IP \fIbindings_return\fP 1i
Returns the binding list.
The caller must allocate sufficient space for the binding list before calling
.PN XrmStringToBindingQuarkList .
.IP \fIquarks_return\fP 1i
Returns the list of quarks.
The caller must allocate sufficient space for the quarks list before calling
.PN XrmStringToBindingQuarkList .
.\" End marker code here
.LP
Component names in the list are separated by a period or
an asterisk character.
The string must be in the format of a valid ResourceName (see section 15.1).
If the string does not start with a period or an asterisk,
a tight binding is assumed.
For example, ``*a.b*c'' becomes:
.LP
.Ds 0
.TA .75i 1.5i 2.25i
.ta .75i 1.5i 2.25i
quarks:    a    b    c
bindings:    loose    tight    loose
.De
.NH 2
Creating and Storing Databases
.XS
\*(SN Creating and Storing Databases
.XE
.LP
.IN "XrmDatabase" "" "@DEF@"
A resource database is an opaque type,
.PN XrmDatabase .
Each database value is stored in an
.PN XrmValue
structure.
This structure consists of a size, an address, and a representation type.
The size is specified in bytes.
The representation type is a way for you to store data tagged by some
application-defined type (for example, ``font'' or ``color'').
It has nothing to do with the C data type or with its class.
The
.PN XrmValue
structure is defined as:
.LP
.IN "XrmValue" "" "@DEF@"
.\" Start marker code here
.Ds 0
.TA .5i 3i
.ta .5i 3i
typedef struct {
    unsigned int size;
    XPointer addr;
} XrmValue, *XrmValuePtr;
.De
.\" End marker code here
.LP
.sp
To initialize the resource manager, use
.PN XrmInitialize .
.IN "XrmInitialize" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmInitialize\^(\|);
.FN
.\" End marker code here
.LP
To retrieve a database from disk, use
.PN XrmGetFileDatabase .
.IN "XrmGetFileDatabase" "" "@DEF@"
.\" Start marker code here
.FD 0
XrmDatabase XrmGetFileDatabase\^(\^\fIfilename\fP\^)
.br
     char *\fIfilename\fP\^;
.FN
.IP \fIfilename\fP 1i
Specifies the resource database file name.
.\" End marker code here
.LP
The
.PN XrmGetFileDatabase
function opens the specified file,
creates a new resource database, and loads it with the specifications
read in from the specified file.
The specified file must contain a sequence of entries in valid ResourceLine
format (see section 15.1).
The file is parsed in the current locale,
and the database is created in the current locale.
If it cannot open the specified file,
.PN XrmGetFileDatabase
returns NULL.
.LP
.sp
To store a copy of a database to disk, use
.PN XrmPutFileDatabase .
.IN "XrmPutFileDatabase" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmPutFileDatabase\^(\^\fIdatabase\fP, \fIstored_db\fP\^)
.br
     XrmDatabase \fIdatabase\fP\^;
.br
     char *\fIstored_db\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the database that is to be used.
.IP \fIstored_db\fP 1i
Specifies the file name for the stored database.
.\" End marker code here
.LP
The
.PN XrmPutFileDatabase
function stores a copy of the specified database in the specified file.
Text is written to the file as a sequence of entries in valid
ResourceLine format (see section 15.1).
The file is written in the locale of the database.
Entries containing resource names that are not in the Host Portable Character
Encoding, or containing values that are not in the encoding of the database
locale, are written in an implementation-dependent manner.
The order in which entries are written is implementation dependent.
Entries with representation types other than ``String'' are ignored.
.LP
.sp
To obtain a pointer to the screen-independent resources of a display, use
.PN XResourceManagerString .
.IN "XResourceManagerString" "" "@DEF@"
.\" Start marker code here
.FD 0
char *XResourceManagerString\^(\^\fIdisplay\fP\^)
.br
      Display *\fIdisplay\fP\^;
.FN
.\" $Header: display.a,v 1.1 88/02/26 10:26:29 mento Exp $
.IP \fIdisplay\fP 1i
Specifies the connection to the X server.
.\" End marker code here
.LP
The
.PN XResourceManagerString
returns the RESOURCE_MANAGER property from the server's root window of screen
zero, which was returned when the connection was opened using
.PN XOpenDisplay .
The property is converted from type STRING to the current locale.
The conversion is identical to that produced by
.PN XmbTextPropertyToTextList
for a singleton STRING property.
The returned string is owned by Xlib, and should not be freed by the client.
Note that the property value must be in a format that is acceptable to
.PN XrmGetStringDatabase .
If no property exists, NULL is returned.
.LP
.sp
To obtain a pointer to the screen-specific resources of a screen, use
.PN XScreenResourceString .
.IN "XScreenResourceString" "" "@DEF@"
.\" Start marker code here
.FD 0
char *XScreenResourceString\^(\^\fIscreen\fP\^)
.br
      Screen *\fIscreen\fP\^;
.FN
.IP \fIscreen\fP 1i
Specifies the screen.
.\" End marker code here
.LP
The
.PN XStringResourceString
returns the SCREEN_RESOURCES property from the root window of the
specified screen.
The property is converted from type STRING to the current locale.
The conversion is identical to that produced by
.PN XmbTextPropertyToTextList
for a singleton STRING property.
Note that the property value must be in a format that is acceptable to
.PN XrmGetStringDatabase .
If no property exists, NULL is returned.
The caller is responsible for freeing the returned string, using
.PN XFree .
.LP
.sp
To create a database from a string, use
.PN XrmGetStringDatabase .
.IN "XrmGetStringDatabase" "" "@DEF@"
.\" Start marker code here
.FD 0
XrmDatabase XrmGetStringDatabase\^(\^\fIdata\fP\^)
.br
     char *\fIdata\fP\^;
.FN
.IP \fIdata\fP 1i
Specifies the database contents using a string.
.\" End marker code here
.LP
The
.PN XrmGetStringDatabase
function creates a new database and stores the resources specified
in the specified null-terminated string.
.PN XrmGetStringDatabase
is similar to
.PN XrmGetFileDatabase
except that it reads the information out of a string instead of out of a file.
The string must contain a sequence of entries in valid ResourceLine
format (see section 15.1).
The string is parsed in the current locale,
and the database is created in the current locale.
.LP
.sp
To obtain locale name of a database, use
.PN XrmLocaleOfDatabase .
.IN "XrmLocaleOfDatabase" "" "@DEF@"
.\" Start marker code here
.FD 0
char *XrmLocaleOfDatabase\^(\^\fIdatabase\fP\^)
.br
      XrmDatabase \fIdatabase\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the resource database.
.\" End marker code here
.LP
The
.PN XrmLocaleOfDatabase
function returns the name of the locale bound to the specified
database, as a null-terminated string.
The returned locale name string is owned by Xlib and should not be
modified or freed by the client.
Xlib is not permitted to free the string until the database is destroyed.
Until the string is freed,
it will not be modified by Xlib.
.LP
.sp
To destroy a resource database and free its allocated memory, use
.PN XrmDestroyDatabase .
.IN "XrmDestroyDatabase" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmDestroyDatabase\^(\^\fIdatabase\fP\^)
.br
      XrmDatabase \fIdatabase\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the resource database.
.\" End marker code here
.LP
If database is NULL,
.PN XrmDestroyDatabase
returns immediately.
.LP
.sp
To associate a resource database with a display, use
.PN XrmSetDatabase .
.IN "XrmSetDatabase" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmSetDatabase\^(\^\fIdisplay\fP\^, \fIdatabase\fP\^)
.br
      Display *\fIdisplay\fP\^;
.br
      XrmDatabase \fIdatabase\fP\^;
.FN
.\" $Header: display.a,v 1.1 88/02/26 10:26:29 mento Exp $
.IP \fIdisplay\fP 1i
Specifies the connection to the X server.
.IP \fIdatabase\fP 1i
Specifies the resource database.
.\" End marker code here
.LP
The
.PN XrmSetDatabase
function associates the specified resource database (or NULL)
with the specified display.
The database previously associated with the display (if any) is not destroyed.
A client or toolkit may find this function convenient for retaining a database
once it is constructed.
.LP
.sp
To get the resource database associated with a display, use
.PN XrmGetDatabase .
.IN "XrmGetDatabase" "" "@DEF@"
.\" Start marker code here
.FD 0
XrmDatabase XrmGetDatabase\^(\^\fIdisplay\fP\^)
.br
      Display *\fIdisplay\fP\^;
.FN
.\" $Header: display.a,v 1.1 88/02/26 10:26:29 mento Exp $
.IP \fIdisplay\fP 1i
Specifies the connection to the X server.
.\" End marker code here
.LP
The
.PN XrmGetDatabase
function returns the database associated with the specified display.
It returns NULL if a database has not yet been set.
.NH 2
Merging Resource Databases
.XS
\*(SN Merging Resource Databases
.XE
.LP
To merge the contents of a resource file into a database, us
.PN XrmCombineFileDatabase .
.IN "XrmCombineFileDatabase" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmCombineFileDatabase(\^\fIfilename\fP, \fItarget_db\fP, \fIoverride\fP\^)
.br
      char *\fIfilename\fP;
.br
      XrmDatabase *\fItarget_db\fP\^;
.br
      Bool \fIoverride\fP;
.FN
.IP \fIfilename\fP 1i
Specifies the resource database file name.
.IP \fItarget_db\fP 1i
Specifies the resource database into which the source
database is to be merged.
.\" End marker code here
.LP
.\" $Header: XrmCFDBase.d,v 1.2 88/06/11 07:54:46 mento Exp $
The
.PN XrmCombineFileDatabase
function merges the contents of a resource file into a database.
If the same specifier is used for an entry in both the file and
the database,
the entry in the file will replace the entry in the database
if override is
.PN True ;
otherwise, the entry in file is discarded.
The file is parsed in the current locale.
If the file cannot be read a zero status is returned;
otherwise a nonzero status is returned.
If target_db contains NULL,
.PN XrmCombineFileDatabase
creates and returns a new database to it.
Otherwise, the database pointed to by target_db is not destroyed by the merge.
The database entries are merged without changing values or types,
regardless of the locale of the database.
The locale of the target database is not modified.
.LP
.sp
To merge the contents of one database into another database, use
.PN XrmCombineDatabase .
.IN "XrmCombineDatabase" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmCombineDatabase(\^\fIsource_db\fP, \fItarget_db\fP, \fIoverride\fP\^)
.br
      XrmDatabase \fIsource_db\fP, *\fItarget_db\fP\^;
.br
      Bool \fIoverride\fP;
.FN
.IP \fIsource_db\fP 1i
Specifies the resource database that is to be merged into the target database.
.IP \fItarget_db\fP 1i
Specifies the resource database into which the source
database is to be merged.
.IP \fIoverride\fP 1i
Specifies whether source entries override target ones.
.\" End marker code here
.LP
.\" $Header: XrmCDBase.d,v 1.2 88/06/11 07:54:46 mento Exp $
The
.PN XrmCombineDatabase
function merges the contents of one database into another.
If the same specifier is used for an entry in both databases,
the entry in the source_db will replace the entry in the target_db
if override is
.PN True ;
otherwise, the entry in source_db is discarded.
If target_db contains NULL,
.PN XrmCombineDatabase
simply stores source_db in it.
Otherwise, source_db is destroyed by the merge, but the database pointed
to by target_db is not destroyed.
The database entries are merged without changing values or types,
regardless of the locales of the databases.
The locale of the target database is not modified.
.LP
.sp
To merge the contents of one database into another database with override
semantics, use
.PN XrmMergeDatabases .
.IN "XrmMergeDatabases" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmMergeDatabases(\^\fIsource_db\fP, \fItarget_db\fP\^)
.br
      XrmDatabase \fIsource_db\fP, *\fItarget_db\fP\^;
.FN
.IP \fIsource_db\fP 1i
Specifies the resource database that is to be merged into the target database.
.IP \fItarget_db\fP 1i
Specifies the resource database into which the source
database is to be merged.
.\" End marker code here
.LP
.\" $Header: XrmMDBase.d,v 1.2 88/06/11 07:54:46 mento Exp $
The
.PN XrmMergeDatabases
function merges the contents of one database into another.
If the same specifier is used for an entry in both databases,
the entry in the source_db will replace the entry in the target_db
(that is, it overrides target_db).
If target_db contains NULL,
.PN XrmMergeDatabases
simply stores source_db in it.
Otherwise, source_db is destroyed by the merge, but the database pointed
to by target_db is not destroyed.
The database entries are merged without changing values or types,
regardless of the locales of the databases.
The locale of the target database is not modified.
.NH 2
Looking Up Resources
.XS
\*(SN Looking Up Resources
.XE
.LP
To retrieve a resource from a resource database, use
.PN XrmGetResource ,
.PN XrmQGetResource ,
or
.PN XrmQGetSearchResource .
.LP
.sp
.IN "XrmGetResource" "" "@DEF@"
.\" Start marker code here
.FD 0
Bool XrmGetResource\^(\^\fIdatabase\fP, \fIstr_name\fP, \fIstr_class\fP, \
\fIstr_type_return\fP, \fIvalue_return\fP\^)
.br
     XrmDatabase \fIdatabase\fP\^;
.br
     char *\fIstr_name\fP\^;
.br
     char *\fIstr_class\fP\^;
.br
     char **\fIstr_type_return\fP\^;
.br
     XrmValue *\fIvalue_return\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the database that is to be used.
.IP \fIstr_name\fP 1i
Specifies the fully qualified name of the value being retrieved (as a string).
.IP \fIstr_class\fP 1i
Specifies the fully qualified class of the value being retrieved (as a string).
.IP \fIstr_type_return\fP 1i
Returns the representation type of the destination (as a string).
.IP \fIvalue_return\fP 1i
Returns the value in the database.
.\" End marker code here
.LP
.sp
.IN "XrmQGetResource" "" "@DEF@"
.\" Start marker code here
.FD 0
Bool XrmQGetResource\^(\^\fIdatabase\fP, \fIquark_name\fP, \fIquark_class\fP, \
\fIquark_type_return\fP, \fIvalue_return\fP\^)
.br
     XrmDatabase \fIdatabase\fP\^;
.br
     XrmNameList \fIquark_name\fP\^;
.br
     XrmClassList \fIquark_class\fP\^;
.br
     XrmRepresentation *\fIquark_type_return\fP\^;
.br
     XrmValue *\fIvalue_return\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the database that is to be used.
.IP \fIquark_name\fP 1i
Specifies the fully qualified name of the value being retrieved (as a quark).
.IP \fIquark_class\fP 1i
Specifies the fully qualified class of the value being retrieved (as a quark).
.IP \fIquark_type_return\fP 1i
Returns the representation type of the destination (as a quark).
.IP \fIvalue_return\fP 1i
Returns the value in the database.
.\" End marker code here
.LP
The
.PN XrmGetResource
and
.PN XrmQGetResource
functions retrieve a resource from the specified database.
Both take a fully qualified name/class pair, a destination
resource representation, and the address of a value
(size/address pair).
The value and returned type point into database memory;
therefore, you must not modify the data.
.LP
The database only frees or overwrites entries on
.PN XrmPutResource ,
.PN XrmQPutResource ,
or
.PN XrmMergeDatabases .
A client that is not storing new values into the database or
is not merging the database should be safe using the address passed
back at any time until it exits.
If a resource was found, both
.PN XrmGetResource
and
.PN XrmQGetResource
return
.PN True ;
otherwise, they return
.PN False .
.LP
.sp
Most applications and toolkits do not make random probes
into a resource database to fetch resources.
The X toolkit access pattern for a resource database is quite stylized.
A series of from 1 to 20 probes are made with only the
last name/class differing in each probe.
The
.PN XrmGetResource
function is at worst a %2 sup n% algorithm,
where \fIn\fP is the length of the name/class list.
This can be improved upon by the application programmer by prefetching a list
of database levels that might match the first part of a name/class list.
.LP
.sp
To obtain a list of database levels, use
.PN XrmQGetSearchList .
.IN "XrmQGetSearchList" "" "@DEF@"
.\" Start marker code here
.FD 0
typedef XrmHashTable *XrmSearchList;
.sp
Bool XrmQGetSearchList\^(\^\fIdatabase\fP, \fInames\fP, \fIclasses\fP, \
\fIlist_return\fP, \fIlist_length\fP\^)
.br
     XrmDatabase \fIdatabase\fP\^;
.br
     XrmNameList \fInames\fP\^;
.br
     XrmClassList \fIclasses\fP\^;
.br
     XrmSearchList \fIlist_return\fP\^;
.br
     int \fIlist_length\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the database that is to be used.
.IP \fInames\fP 1i
Specifies a list of resource names.
.IP \fIclasses\fP 1i
Specifies a list of resource classes.
.IP \fIlist_return\fP 1i
Returns a search list for further use.
The caller must allocate sufficient space for the list before calling
.PN XrmQGetSearchList .
.IP \fIlist_length\fP 1i
Specifies the number of entries (not the byte size) allocated for list_return.
.\" End marker code here
.LP
.EQ
delim %%
.EN
The
.PN XrmQGetSearchList
function takes a list of names and classes
and returns a list of database levels where a match might occur.
The returned list is in best-to-worst order and
uses the same algorithm as
.PN XrmGetResource
for determining precedence.
If list_return was large enough for the search list,
.PN XrmQGetSearchList
returns
.PN True ;
otherwise, it returns
.PN False .
.LP
The size of the search list that the caller must allocate is
dependent upon the number of levels and wildcards in the resource specifiers
that are stored in the database.
The worst case length is %3 sup n%,
where \fIn\fP is the number of name or class components in names or classes.
.LP
When using
.PN XrmQGetSearchList
followed by multiple probes for resources with a common name and class prefix,
only the common prefix should be specified in the name and class list to
.PN XrmQGetSearchList .
.LP
.sp
To search resource database levels for a given resource, use
.PN XrmQGetSearchResource .
.IN "XrmQGetSearchResource" "" "@DEF@"
.\" Start marker code here
.FD 0
Bool XrmQGetSearchResource\^(\^\fIlist\fP, \fIname\fP, \fIclass\fP, \
\fItype_return\fP, \fIvalue_return\fP\^)
.br
     XrmSearchList \fIlist\fP\^;
.br
     XrmName \fIname\fP\^;
.br
     XrmClass \fIclass\fP\^;
.br
     XrmRepresentation *\fItype_return\fP\^;
.br
     XrmValue *\fIvalue_return\fP\^;
.FN
.IP \fIlist\fP 1i
Specifies the search list returned by
.PN XrmQGetSearchList .
.IP \fIname\fP 1i
Specifies the resource name.
.IP \fIclass\fP 1i
Specifies the resource class.
.IP \fItype_return\fP 1i
Returns data representation type.
.IP \fIvalue_return\fP 1i
Returns the value in the database.
.\" End marker code here
.LP
The
.PN XrmQGetSearchResource
function searches the specified database levels for the resource
that is fully identified by the specified name and class.
The search stops with the first match.
.PN XrmQGetSearchResource
returns
.PN True
if the resource was found;
otherwise, it returns
.PN False .
.LP
A call to
.PN XrmQGetSearchList
with a name and class list containing all but the last component
of a resource name followed by a call to
.PN XrmQGetSearchResource
with the last component name and class returns the same database entry as
.PN XrmGetResource
and
.PN XrmQGetResource
with the fully qualified name and class.
.NH 2
Storing Into a Resource Database
.XS
\*(SN Storing Into a Resource Database
.XE
.LP
To store resources into the database, use
.PN XrmPutResource
or
.PN XrmQPutResource .
Both functions take a partial resource specification, a
representation type, and a value.
This value is copied into the specified database.
.LP
.sp
.IN "XrmPutResource" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmPutResource\^(\^\fIdatabase\fP, \fIspecifier\fP, \fItype\fP, \fIvalue\fP\^)
.br
     XrmDatabase *\fIdatabase\fP\^;
.br
     char *\fIspecifier\fP\^;
.br
     char *\fItype\fP\^;
.br
     XrmValue *\fIvalue\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the resource database.
.IP \fIspecifier\fP 1i
Specifies a complete or partial specification of the resource.
.IP \fItype\fP 1i
Specifies the type of the resource.
.IP \fIvalue\fP 1i
Specifies the value of the resource, which is specified as a string.
.\" End marker code here
.LP
If database contains NULL,
.PN XrmPutResource
creates a new database and returns a pointer to it.
.PN XrmPutResource
is a convenience function that calls
.PN XrmStringToBindingQuarkList
followed by:
.LP
.Ds
XrmQPutResource(database, bindings, quarks, XrmStringToQuark(type), value)
.De
If the specifier and type are not in the Host Portable Character Encoding
the result is implementation dependent.
The value is stored in the database without modification.
.LP
.sp
.IN "XrmQPutResource" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmQPutResource\^(\^\fIdatabase\fP, \fIbindings\fP, \fIquarks\fP, \
\fItype\fP, \fIvalue\fP\^)
.br
     XrmDatabase *\fIdatabase\fP\^;
.br
     XrmBindingList \fIbindings\fP\^;
.br
     XrmQuarkList \fIquarks\fP\^;
.br
     XrmRepresentation \fItype\fP\^;
.br
     XrmValue *\fIvalue\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the resource database.
.IP \fIbindings\fP 1i
Specifies a list of bindings.
.IP \fIquarks\fP 1i
Specifies the complete or partial name or the class list of the resource.
.IP \fItype\fP 1i
Specifies the type of the resource.
.IP \fIvalue\fP 1i
Specifies the value of the resource, which is specified as a string.
.\" End marker code here
.LP
If database contains NULL,
.PN XrmQPutResource
creates a new database and returns a pointer to it.
If a resource entry with the identical bindings and quarks already
exists in the database, the previous value is replaced by the new
specified value.
The value is stored in the database without modification.
.LP
.sp
To add a resource that is specified as a string, use
.PN XrmPutStringResource .
.IN "XrmPutStringResource" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmPutStringResource\^(\^\fIdatabase\fP, \fIspecifier\fP, \fIvalue\fP\^)
.br
     XrmDatabase *\fIdatabase\fP\^;
.br
     char *\fIspecifier\fP\^;
.br
     char *\fIvalue\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the resource database.
.IP \fIspecifier\fP 1i
Specifies a complete or partial specification of the resource.
.IP \fIvalue\fP 1i
Specifies the value of the resource, which is specified as a string.
.\" End marker code here
.LP
If database contains NULL,
.PN XrmPutStringResource
creates a new database and returns a pointer to it.
.PN XrmPutStringResource
adds a resource with the specified value to the specified database.
.PN XrmPutStringResource
is a convenience function that first calls
.PN XrmStringToBindingQuarkList
on the specifier and then calls
.PN XrmQPutResource ,
using a ``String'' representation type.
If the specifier is not in the Host Portable Character Encoding
the result is implementation dependent.
The value is stored in the database without modification.
.LP
.sp
To add a string resource using quarks as a specification, use
.PN XrmQPutStringResource .
.IN "XrmQPutStringResource" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmQPutStringResource\^(\^\fIdatabase\fP, \fIbindings\fP, \fIquarks\fP, \
\fIvalue\fP\^)
.br
     XrmDatabase *\fIdatabase\fP\^;
.br
     XrmBindingList \fIbindings\fP\^;
.br
     XrmQuarkList \fIquarks\fP\^;
.br
     char *\fIvalue\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the resource database.
.IP \fIbindings\fP 1i
Specifies a list of bindings.
.IP \fIquarks\fP 1i
Specifies the complete or partial name or the class list of the resource.
.IP \fIvalue\fP 1i
Specifies the value of the resource, which is specified as a string.
.\" End marker code here
.LP
If database contains NULL,
.PN XrmQPutStringResource
creates a new database and returns a pointer to it.
.PN XrmQPutStringResource
is a convenience routine that constructs an
.PN XrmValue
for the value string (by calling
.PN strlen
to compute the size) and
then calls
.PN XrmQPutResource ,
using a ``String'' representation type.
The value is stored in the database without modification.
.LP
.sp
To add a single resource entry that is specified as a string that contains
both a name and a value, use
.PN XrmPutLineResource .
.IN "XrmPutLineResource" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmPutLineResource\^(\^\fIdatabase\fP, \fIline\fP\^)
.br
     XrmDatabase *\fIdatabase\fP\^;
.br
     char *\fIline\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the resource database.
.IP \fIline\fP 1i
Specifies the resource name and value pair as a single string.
.\" End marker code here
.LP
If database contains NULL,
.PN XrmPutLineResource
creates a new database and returns a pointer to it.
.PN XrmPutLineResource
adds a single resource entry to the specified database.
The line must be in valid ResourceLine format (see section 15.1).
The string is parsed in the locale of the database.
If the
.PN ResourceName
is not in the Host Portable Character Encoding
the result is implementation dependent.
Note that comment lines are not stored.
.NH 2
Enumerating Database Entries
.XS
\*(SN Enumerating Database Entries
.XE
.LP
To enumerate the entries of a database, use
.PN XrmEnumerateDatabase .
.IN "XrmEnumerateDatabase" "" "@DEF@"
.\" Start marker code here
.FD 0
.TS
lw(.5i) lw(2i) lw(2.5i).
T{
#define
T}    T{
.PN XrmEnumAllLevels
T}    T{
0
T}
T{
#define
T}    T{
.PN XrmEnumOneLevel
T}    T{
1
T}
.TE
.sp
Bool XrmEnumerateDatabase\^(\^\fIdatabase\fP, \fIname_prefix\fP, \fIclass_prefix\fP, \fImode\fP, \fIproc\fP, \fIarg\fP\^)
.br
      XrmDatabase \fIdatabase\fP\^;
.br
      XrmNameList \fIname_prefix\fP\^;
.br
      XrmClassList \fIclass_prefix\fP\^;
.br
      int \fImode\fP\^;
.br
      Bool (\^*\fIproc\fP\^)\^(\^)\^;
.br
      XPointer \fIarg\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the resource database.
.IP \fIname_prefix\fP 1i
Specifies the resource name prefix.
.IP \fIclass_prefix\fP 1i
Specifies the resource class prefix.
.IP \fImode\fP 1i
Specifies the number of levels to enumerate.
.IP \fIproc\fP 1i
Specifies the procedure that is to be called for each matching entry.
.IP \fIarg\fP 1i
Specifies the user-supplied argument that will be passed to the procedure.
.\" End marker code here
.LP
The
.PN XrmEnumerateDatabase
function calls the specified procedure for each resource in the database
that would match some completion of the given name/class resource prefix.
The order in which resources are found is implementation-dependent.
If mode is
.PN XrmEnumOneLevel ,
then a resource must match the given name/class prefix with
just a single name and class appended.  If mode is
.PN XrmEnumAllLevels ,
the resource must match the given name/class prefix with one or more names and
classes appended.
If the procedure returns
.PN True ,
the enumeration terminates and the function returns
.PN True .
If the procedure always returns
.PN False ,
all matching resources are enumerated and the function returns
.PN False .
.LP
The procedure is called with the following arguments:
.LP
.\" Start marker code here
.Ds 0
.TA .5i 3i
.ta .5i 3i
(*\fIproc\fP\^)(\^\fIdatabase\fP, \fIbindings\fP, \fIquarks\fP, \fItype\fP, \fIvalue\fP, \fIarg\fP\^)
    XrmDatabase *\fIdatabase\fP\^;
    XrmBindingList \fIbindings\fP\^;
    XrmQuarkList \fIquarks\fP\^;
    XrmRepresentation *\fItype\fP\^;
    XrmValue *\fIvalue\fP\^;
    XPointer \fIclosure\fP\^;
.De
.\" End marker code here
.LP
The bindings and quarks lists are terminated by
.PN NULLQUARK .
Note that pointers
to the database and type are passed, but these values should not be modified.
.NH 2
Parsing Command Line Options
.XS
\*(SN Parsing Command Line Options
.XE
.LP
The
.PN XrmParseCommand
function can be used to parse the command line arguments to a program
and modify a resource database with selected entries from the command line.
.LP
.IN "XrmOptionKind" "" "@DEF@"
.\" Start marker code here
.Ds 0
.TA .5i 2.5i
.ta .5i 2.5i
typedef enum {
    XrmoptionNoArg,    /* Value is specified in XrmOptionDescRec.value */
    XrmoptionIsArg,    /* Value is the option string itself */
    XrmoptionStickyArg,    /* Value is characters immediately following option */
    XrmoptionSepArg,    /* Value is next argument in argv */
    XrmoptionResArg,    /* Resource and value in next argument in argv */
    XrmoptionSkipArg,    /* Ignore this option and the next argument in argv */
    XrmoptionSkipLine,    /* Ignore this option and the rest of argv */
    XrmoptionSkipNArgs    /* Ignore this option and the next
        \ \ \ XrmOptionDescRec.value arguments in argv */
} XrmOptionKind;
.De
.\" End marker code here
.LP
Note that
.PN XrmoptionSkipArg
is equivalent to
.PN XrmoptionSkipNArgs
with the
.PN XrmOptionDescRec.value
field containing the value one.
Note also that the value zero for
.PN XrmoptionSkipNArgs
indicates that only the option itself is to be skipped.
.LP
.IN "XrmOptionDescRec" "" "@DEF@"
.\" Start marker code here
.Ds 0
.TA .5i 2.5i
.ta .5i 2.5i
typedef struct {
    char *option;    /* Option specification string in argv            */
    char *specifier;    /* Binding and resource name (sans application name)    */
    XrmOptionKind argKind;    /* Which style of option it is        */
    XPointer value;    /* Value to provide if XrmoptionNoArg or
        \ \ \ XrmoptionSkipNArgs   */
} XrmOptionDescRec, *XrmOptionDescList;
.De
.\" End marker code here
.LP
.sp
To load a resource database from a C command line, use
.PN XrmParseCommand .
.IN "XrmParseCommand" "" "@DEF@"
.\" Start marker code here
.FD 0
void XrmParseCommand\^(\^\fIdatabase\fP\^, \^\fItable\fP\^, \^\fItable_count\fP\^, \
\^\fIname\fP\^, \^\fIargc_in_out\fP\^, \^\fIargv_in_out\fP\^)
.br
      XrmDatabase *\fIdatabase\fP\^;
.br
      XrmOptionDescList \fItable\fP\^;
.br
      int \fItable_count\fP\^;
.br
      char *\fIname\fP\^;
.br
      int *\fIargc_in_out\fP\^;
.br
      char **\fIargv_in_out\fP\^;
.FN
.IP \fIdatabase\fP 1i
Specifies the resource database.
.IP \fItable\fP 1i
Specifies the table of command line arguments to be parsed.
.IP \fItable_count\fP 1i
Specifies the number of entries in the table.
.\" $Header: parname.a,v 1.1 88/02/26 10:30:16 mento Exp $
.IP \fIname\fP 1i
Specifies the application name.
.IP \fIargc_in_out\fP 1i
Specifies the number of arguments and returns the number of remaining arguments.
.IP \fIargv_in_out\fP 1i
Specifies the command line arguments
and returns the remaining arguments.
.\" End marker code here
.LP
.\" $Header: XrmParse.d,v 1.7 88/08/20 10:49:05 mento Exp $
The
.PN XrmParseCommand
function parses an (argc, argv) pair according to the specified option table,
loads recognized options into the specified database with type ``String,''
and modifies the (argc, argv) pair to remove all recognized options.
If database contains NULL,
.PN XrmParseCommand
creates a new database and returns a pointer to it.
Otherwise, entries are added to the database specified.
If a database is created, it is created in the current locale.
.LP
The specified table is used to parse the command line.
Recognized options in the table are removed from argv,
and entries are added to the specified resource database.
The table entries contain information on the option string,
the option name, the style of option,
and a value to provide if the option kind is
.PN XrmoptionNoArg .
The option names are compared byte-for-byte to arguments in argv,
independent of any locale.
The resource values given in the table are stored in the resource database
without modification.
All resource database entries are created
using a ``String'' representation type.
The argc argument specifies the number of arguments in argv
and is set on return to the remaining number of arguments that were not parsed.
The name argument should be the name of your application
for use in building the database entry.
The name argument is prefixed to the resourceName in the option table
before storing a database entry.
No separating (binding) character is inserted,
so the table must contain either a period (.) or an asterisk (*)
as the first character in each resourceName entry.
To specify a more completely qualified resource name,
the resourceName entry can contain multiple components.
If the name argument and the resourceNames are not in the
Host Portable Character Encoding the result is implementation dependent.
.LP
The following provides a sample option table:
.LP
.Ds 0
.TA 1.25i 3.25i 4.75i
.ta 1.25i 3.25i 4.75i
static XrmOptionDescRec opTable[] = {
{"\-background",    "*background",    XrmoptionSepArg,    (XPointer) NULL},
{"\-bd",    "*borderColor",    XrmoptionSepArg,    (XPointer) NULL},
{"\-bg",    "*background",    XrmoptionSepArg,    (XPointer) NULL},
{"\-borderwidth",    "*TopLevelShell.borderWidth",    XrmoptionSepArg,    (XPointer) NULL},
{"\-bordercolor",    "*borderColor",    XrmoptionSepArg,    (XPointer) NULL},
{"\-bw",    "*TopLevelShell.borderWidth",    XrmoptionSepArg,    (XPointer) NULL},
{"\-display",    ".display",    XrmoptionSepArg,    (XPointer) NULL},
{"\-fg",    "*foreground",    XrmoptionSepArg,    (XPointer) NULL},
{"\-fn",    "*font",    XrmoptionSepArg,    (XPointer) NULL},
{"\-font",    "*font",    XrmoptionSepArg,    (XPointer) NULL},
{"\-foreground",    "*foreground",    XrmoptionSepArg,    (XPointer) NULL},
{"\-geometry",    ".TopLevelShell.geometry",    XrmoptionSepArg,    (XPointer) NULL},
{"\-iconic",    ".TopLevelShell.iconic",    XrmoptionNoArg,    (XPointer) "on"},
{"\-name",    ".name",    XrmoptionSepArg,    (XPointer) NULL},
{"\-reverse",    "*reverseVideo",    XrmoptionNoArg,    (XPointer) "on"},
{"\-rv",    "*reverseVideo",    XrmoptionNoArg,    (XPointer) "on"},
{"\-synchronous",    "*synchronous",    XrmoptionNoArg,    (XPointer) "on"},
{"\-title",    ".TopLevelShell.title",    XrmoptionSepArg,    (XPointer) NULL},
{"\-xrm",    NULL,    XrmoptionResArg,    (XPointer) NULL},
};
.De
.LP
In this table, if the \-background (or \-bg) option is used to set
background colors, the stored resource specifier matches all
resources of attribute background.
If the \-borderwidth option is used,
the stored resource specifier applies only to border width
attributes of class TopLevelShell (that is, outer-most windows, including
pop-up windows).
If the \-title option is used to set a window name,
only the topmost application windows receive the resource.
.LP
When parsing the command line,
any unique unambiguous abbreviation for an option name in the table is
considered a match for the option.
Note that uppercase and lowercase matter.
.bp