realpath - output real file name/pathname

Syntax	#include <stdlib.h> char *realpath (const char *file_name, char *resolved_name);
Description	From the pathname specified in file_name, realpath() derives an absolute pathname in which all symbolic links and references to ’.’ and ’..’ are resolved. This “real” pathname is stored in resolved_name up to {MAX_PATH} bytes. Both relative and absolute pathnames can be processed. With absolute pathnames and relative pathnames whose resolved name cannot be printed out relatively (e.g. ../../reldir), the resolved absolute name is returned. For the other relative pathnames the resolved relative name is returned. resolved_name must be large enough to incorporate the resolved pathname.
Return val.	Pointer to resolved_name
		if successful.
	Null pointer	otherwise. errno is set to indicate the error.
Errors	realpath() will fail if:
	EACCES	Read or search permission is denied for a component of file_name.
	EINVAL	The file_name or resolved_name argument is a null pointer.
	EIO	An I/O error occurred during reading from the file system.
	ENAMETOOLONG
		The length of the file_name argument exceeds {PATH_MAX}, or the length of a component of file_name exceeds {NAME_MAX}. In resolving a symbolic link, a interim result was produced whose length exceeds {PATH_MAX}.
	ENOENT	A component of the path prefix does not exist or file_name is an empty string.
	ENOTDIR	A component of the path prefix is not a directory.
	ENOMEM	There is no longer enough memory available.
Notes	realpath() handles null-terminated strings. You should have execution permission for all directories in the given and resolved path. In certain circumstances realpath() may not return to the current directory if an error occurs.
See also	getcwd(), sysconf(), stdlib.h.