opendir, fdopendir - open directory

Syntax	#include <dirent.h> Optional #include <sys/types.h> (End) DIR *opendir(const char *dirname); DIR *fdopendir(int fd);
Description	opendir() opens a directory stream corresponding to the directory named by dirname. The directory stream is positioned at the first entry. The type DIR, which is defined in dirent.h, represents a directory stream that is an ordered sequence of all directory entries in a special directory. Since the type DIR is implemented in POSIX using a file descriptor, applications can only open a maximum of {OPEN_MAX} files and directories. If dirname cannot be accessed or is not a directory, or if not enough memory to hold a DIR structure or a buffer for the directory entries can be allocated with malloc(), a null pointer is returned. The fdopendir() function is equivalent to the opendir() function, with the difference that the directory is specified by the file descriptor fd instead of by a pathname. After a successful return from fdopendir(), the file descriptor is under system control. If an attempt is made to close the file descriptor or to change the status of the directory by functions other than closedir(), readdir(), rewinddir() or seekdir(), the behavior is undefined. closedir() also closes the file descriptor.
Return val.	Pointer to a DIR object
		if successful.
	Null pointer	if an error occurs. errno is set to indicate the error.
Errors	opendir() and fdopendir() will fail if:
	EACCES	Search permission is denied for the component of dirname or read permission is denied for dirname.
	Extension
	EFAULT	dirname points outside the allocated address space of the process.
	ELOOP	Too many symbolic links were encountered in resolving dirname. (End)
	EMFILE	More than {OPEN_MAX} file descriptors are currently open in the calling process.
	ENAMETOOLONG
	The length of the dirname argument exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}.
	ENFILE	Too many file descriptors are currently open in the system.
	ENOENT	dirname points to the name of a file that does not exist or to an empty string.
	ENOTDIR	A component of dirname is not a directory.
	In addition, fdopendir() fails if the following applies:
	EBADF	The fd parameter contains no valid file descriptor which is opened for reading.
	ENOTDIR	The file descriptor fd is not connected with a directory.
Notes	opendir() should be used in conjunction with readdir(), closedir() and rewinddir() to examine the contents of the directory (see also readdir()). This method is recommended for portability. opendir() is executed only for POSIX files
See also	closedir(), readdir(), rewinddir(), dirent.h, sys/types.h, limits.h.