cscope is an interactive, screen-oriented tool that allows the user to browse through C source files for specified elements of code. By default, cscope examines the C (.c and .h), lex (.l), and yacc (.y) source files in the current directory. cscope may also be invoked for source files named on the command line. In either case, cscope searches the standard directories for #include files that it does not find in the current directory. cscope uses a symbol cross-reference, cscope.out by default, to locate functions, function calls, macros, variables, and preprocessor symbols in the files. cscope builds the symbol cross-reference the first time it is used on the source files for the program being browsed. On a subsequent invocation, cscope rebuilds the cross-reference only if a source file has changed or the list of source files is different. When the cross-reference is rebuilt, the data for the unchanged files are copied from the old cross-reference, which makes rebuilding faster than the initial build.