Linux Manual Pages

Free Software * Books

Source Code

Free Media

Linux

Tcl_GetIndexFromObj

HOME

Tcl_GetIndexFromObj

NAME
SYNOPSIS
ARGUMENTS
DESCRIPTION
SEE ALSO
KEYWORDS

___________________________

NAME

Tcl_GetIndexFromObj, Tcl_GetIndexFromObjStruct − lookup string in table of keywords

SYNOPSIS

#include <tcl.h>

int
Tcl_GetIndexFromObj(interp, objPtr, tablePtr, msg, flags,
indexPtr)

int
Tcl_GetIndexFromObjStruct(interp, objPtr, structTablePtr, offset,
msg, flags, indexPtr)

ARGUMENTS

	Tcl_Interp *interp (in)		Interpreter to use for error reporting; if NULL, then no message is provided on errors.
	Tcl_Obj *objPtr (in/out)		The string value of this object is used to search through tablePtr. The internal representation is modified to hold the index of the matching table entry.
	const char **tablePtr (in)		An array of null-terminated strings. The end of the array is marked by a NULL string pointer.
	const void *structTablePtr (in)		An array of arbitrary type, typically some struct type. The first member of the structure must be a null-terminated string. The size of the structure is given by offset.
	int offset (in)		The offset to add to structTablePtr to get to the next entry. The end of the array is marked by a NULL string pointer.
	const char *msg (in)		Null-terminated string describing what is being looked up, such as option. This string is included in error messages.
	int flags (in)		OR-ed combination of bits providing additional information for operation. The only bit that is currently defined is TCL_EXACT.
	int *indexPtr (out)		The index of the string in tablePtr that matches the value of objPtr is returned here.

______________

DESCRIPTION

This procedure provides an efficient way for looking up keywords, switch names, option names, and similar things where the value of an object must be one of a predefined set of values. ObjPtr is compared against each of the strings in tablePtr to find a match. A match occurs if objPtr’s string value is identical to one of the strings in tablePtr, or if it is a non-empty unique abbreviation for exactly one of the strings in tablePtr and the TCL_EXACT flag was not specified; in either case the index of the matching entry is stored at *indexPtr and TCL_OK is returned.

If there is no matching entry, TCL_ERROR is returned and an error message is left in interp’s result if interp is not NULL. Msg is included in the error message to indicate what was being looked up. For example, if msg is option the error message will have a form like “bad option "firt": must be first, second, or third”.

If Tcl_GetIndexFromObj completes successfully it modifies the internal representation of objPtr to hold the address of the table and the index of the matching entry. If Tcl_GetIndexFromObj is invoked again with the same objPtr and tablePtr arguments (e.g. during a reinvocation of a Tcl command), it returns the matching index immediately without having to redo the lookup operation. Note: Tcl_GetIndexFromObj assumes that the entries in tablePtr are static: they must not change between invocations. If the value of objPtr is the empty string, Tcl_GetIndexFromObj will treat it as a non-matching value and return TCL_ERROR.

Tcl_GetIndexFromObjStruct works just like Tcl_GetIndexFromObj, except that instead of treating tablePtr as an array of string pointers, it treats it as a pointer to the first string in a series of strings that have offset bytes between them (i.e. that there is a pointer to the first array of characters at tablePtr, a pointer to the second array of characters at tablePtr+offset bytes, etc.) This is particularly useful when processing things like Tk_ConfigurationSpec, whose string keys are in the same place in each of several array elements.

KEYWORDS

index, object, table lookup

Opportunity

Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.

Education

Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.