`<dir.h>`

`chdir`	Changes current directory.
`findfirst`	Searches a disk directory.
`findnext`	Continues findfirst search.
`fnmerge`	Builds a path from component parts.
`fnsplit`	Splits a full path name into its components.
`getcurdir`	Gets current directory for specified drive.
`getcwd`	Gets current working directory.
`getdisk, setdisk`	Gets or set the current drive number.
`mkdir`	Creates a directory.
`mktemp`	Makes a unique file name.
`rmdir`	Removes a DOS file directory.
`searchpath`	Searches the DOS path for a file.