The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 10, 1996
Filed:
Mar. 09, 1994
Erik Crank, Travis County, TX (US);
Jon Bellin, Travis County, TX (US);
National Instruments Corporation, Austin, TX (US);
Abstract
A method and apparatus for performing runtime checking during program execution in a compiled environment using the full ANSI-C programming language. The present invention detects a number of errors during runtime that cannot be found by a compiler at the precise moment that a respective C language restriction is violated. The present invention also provides the user with a direct indication of the problem, thus saving debugging time. The runtime checking features of the present invention further detects when a user is using library functions improperly. When C source code is compiled, the present invention allocates special data structures for every pointer, array and structure object in the program. An association is made between each of these objects, and its special data structure in the compiler symbol table. At runtime, these data structures contain status information about their associated objects. The present invention also inserts special machine language instructions for C expressions during compilation that either modify values in the special data structures or call internal runtime checking functions according to the present invention that use the information in the respective data structures to determine whether an expression is illegal and report errors if necessary. The runtime checking features of the present invention include a method for specifying precise restrictions on the arguments that may be passed to library functions. These restrictions are used to determine whether arguments to library functions conform to their respective restrictions and reports any violations to the user at runtime, indicating which argument caused the error and which restriction was violated.