Một số chức năng khác sẽ được sử dụng bởi các chương trình hoặc mở rộng bảng ký hiệu muốn để thêm các hình thức bổ sung của sự tương tác (chẳng hạn như một giao diện hoặc truy cập cơ sở dữ liệu). Bảng mô tả các chức năng này. Bảng khác Symbol Bảng chức năng | Linux Programming 758 Unleashed Other Functions Some other functions will be used by programs or symbol table extensions that want to add additional forms of interaction such as a GUI or database access . Table describes these functions. Table Other Symbol Table Functions Function Description st_set This function takes a smart pointer two strings a variable name and a value and assigns the value to the variable after looking up the variable in the symbol table pointed to by the smart pointer. st_walk st_walk_next These two functions are used to traverse a symbol table stopping at each variable or member. st_lookup This function is used to find a given identifier within a symbol table. st_find_attrib This function is used to retrieve the value of an attribute associated with a symbol table or subset. st_tostring These two functions invoke the text st_from_string conversion methods associated with a basetype. userchange main This section covers the main function piece-by-piece starting with the declarations. We need to declare main in the traditional manner with argc and argv to have access to the command-line parameters. main argc argv int argc char argv I or char argv l passwd_t options char command 256 FILE pipe FILE rc_file st_show_opt_t st_show_options In the first block we read a configuration file. In this case the file will be named in the current directory. In a typical application you might want to try reading a couple different files and HOME in succession. We must open the file ourselves the symbol table library does not do that for us. In the event of failure we will simply skip the remainder of this block of code. 759 A Symbol Table Library Appendix a The options symbol table options_st was previously defined to include a random assortment of variables including the hostname for remote operation the operation to be performed the debugging level for the symbol table package the passwd structure that
