XLIB FUNCTIONS XrmGetResource(3x11)
NAME
XrmGetResource, XrmQGetResource, XrmQGetSearchList, XrmQGet-
SearchResource - retrieve database resources and search
lists SYNTAXcc [ flag... ] file... -lX11 [ library... ]
Bool XrmGetResource(XrmDatabase database, char *str_name,
char *str_class, char **str_type_return, XrmValue
*value_return);
Bool XrmQGetResource(XrmDatabase database, XrmNameListquark_name, XrmClassList quark_class, XrmRepresentation
*quark_type_return, XrmValue *value_return);
typedef XrmHashTable *XrmSearchList;Bool XrmQGetSearchList(XrmDatabase database, XrmNameL-
ist names, XrmClassList classes, XrmSearchListlist_return, int list_length);
Bool XrmQGetSearchResource(XrmSearchList list, XrmName name,
XrmClass class, XrmRepresentation *type_return,
XrmValue *value_return);
ARGUMENTS class Specifies the resource class. classes Specifies a list of resource classes. database Specifies the database that is to be used.list Specifies the search list returned by XrmQGetSear-
chList.list_length
Specifies the number of entries (not the bytesize) allocated for list_return.
list_return
Returns a search list for further use. name Specifies the resource name. names Specifies a list of resource names.quark_class
Specifies the fully qualified class of the value being retrieved (as a quark).quark_name
X Version 11 Last change: libX11 1.3.5 1 XLIB FUNCTIONS XrmGetResource(3x11) Specifies the fully qualified name of the value being retrieved (as a quark).quark_type_return
Returns the representation type of the destination (as a quark).str_class Specifies the fully qualified class of the value
being retrieved (as a string).str_name Specifies the fully qualified name of the value
being retrieved (as a string).str_type_return
Returns the representation type of the destination (as a string).type_return
Returns data representation type.value_return
Returns the value in the database.DESCRIPTION
The XrmGetResource and XrmQGetResource functions retrieve a resource from the specified database. Both take a fullyqualified name/class pair, a destination resource represen-
tation, and the address of a value (size/address pair). Thevalue and returned type point into database memory; there-
fore, you must not modify the data.The database only frees or overwrites entries on XrmPu-
tResource, XrmQPutResource, or 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 XrmGetResource and XrmQGetResource return True; other-
wise, they return False. The XrmQGetSearchList function takes a list of names and classes and returns a list of database levels where a matchmight occur. The returned list is in best-to-worst order
and uses the same algorithm as XrmGetResource for determin-
ing precedence. If list_return was large enough for the
search list, XrmQGetSearchList returns True; otherwise, it returns False. 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. Theworst case length is %3 sup n%, where n is the number of
name or class components in names or classes. X Version 11 Last change: libX11 1.3.5 2 XLIB FUNCTIONS XrmGetResource(3x11) When using XrmQGetSearchList followed by multiple probes forresources with a common name and class prefix, only the com-
mon prefix should be specified in the name and class list to XrmQGetSearchList.The XrmQGetSearchResource function searches the specified
database levels for the resource that is fully identified by the specified name and class. The search stops with thefirst match. XrmQGetSearchResource returns True if the
resource was found; otherwise, it returns False.A call to XrmQGetSearchList with a name and class list con-
taining all but the last component of a resource name fol-
lowed by a call to XrmQGetSearchResource with the last com-
ponent name and class returns the same database entry as XrmGetResource and XrmQGetResource with the fully qualified name and class. MATCHING RULES 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 the characters ``*'' and ``?'' are not permitted). The library supports up to 100 componentsin a full name or class. Resources are stored in the data-
base 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 the character ``?'')must be specified. The lookup algorithm searches the data-
base 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. 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 selectsa single entry over all others. The rules, in order of pre-
cedence, are: 1. An entry that contains a matching component (whether name, class, or the character ``?'') takes precedence over entries that elide the level (that is, entries X Version 11 Last change: libX11 1.3.5 3 XLIB FUNCTIONS XrmGetResource(3x11) that match the level in a loose binding). 2. An entry with a matching name takes precedence over both entries with a matching class and entries that match using the character ``?''. An entry with a matching class takes precedence over entries that match using the character ``?''. 3. An entry preceded by a tight binding takes precedence over entries preceded by a loose binding.SEE ALSO
XrmInitialize(3x11), XrmMergeDatabases(3x11), XrmPutResource(3x11), XrmUniqueQuark(3x11)Xlib - C Language X Interface
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | x11/library/libx11 ||_____________________________|_____________________________|
| Interface Stability | Committed ||_____________________________|_____________________________|
| MT-Level | See XInitThreads(3X11) |
|_____________________________|_____________________________|
X Version 11 Last change: libX11 1.3.5 4