PHP Developer's Dictionary- P73:PHP is an open source, server-side, HTML-embedded scripting language used to create dynamically generated Web pages. With an easy-to-use syntax and a large, extensible library of modules, PHP brings together the best of Perl, C++, and other languages. | PHP Developer s Dictionary Description The set_fiie_buffer function sets the buffering for write operations to the file referenced by fp to buffer bytes. If the buffer parameter is 0 write operations are unbuffered. is_dir Syntax bool is_dir string filename Description The is_ dir function returns true 1 if filename exists and is a directory. Note The results of this function are cached by PHP. Any subsequent calls to is_dir will return the same results even if the environment has changed. The cache is cleared through the clearstatcache function. is_executable Syntax bool is_executable string filename Description The is_ executable function returns true 1 if the filename exists and is executable. On UNIX systems this will also return true 1 if a directory has the execute permission set. Note The results of this function are cached by PHP. Any subsequent calls to is_executable will return the same results even if the environment has changed. The cache is cleared through the clearstatcache function. IT-SC book 360 PHP Developer s Dictionary is_file Syntax bool is_file string filename Description The is_fiie function returns true 1 if the filename exists and is a file. Note The results of this function are cached by PHP. Any subsequent calls to is_fiie will return the same results even if the environment has changed. The cache is cleared through the clearstatcache function. is_link Syntax bool is_link string filename Description The is_link function returns true 1 if the filename exists and is a symbolic link. Note The results of this function are cached by PHP. Any subsequent calls to is_link will return the same results even if the environment has changed. The cache is cleared through the clearstatcache function. is_readable Syntax IT-SC book 361 PHP Developer s Dictionary bool is_readable string filename Description The is_ readabie function returns true 1 if the filename exists and is readable. On UNIX systems this will also return true 1 if a directory has the .