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opendir
Opens a directory stream.
Syntax
#include <sys/types.h>
#include <dirent.h>
DIR *opendir (const char *pathname);
Parameters
pathname A pointer to a string containing a pathname of a directory to
open. The pathname must be terminated by a null character.
Return Values
<>NULL Success. A pointer to an object of type DIR is returned.
NULL An error occurred. The directory is not opened, and errno is
set to indicate the error condition.
Description
The opendir() function opens a directory stream associated with the
directory specified by pathname and returns a pointer to the open
directory stream to be used by subsequent calls to readdir(),
rewinddir(), and closedir().
The directory stream is positioned at the first entry in the directory.
Implementation Considerations
Refer to the EFAULT, EIMPL, EMFILE, and ESYSERR error descriptions below.
The type DIR (defined in <dirent.h>) is implemented using a file
descriptor. Applications can only open a total of {OPEN_MAX} files and
directories.
The FD_CLOEXEC flag is not currently supported.
Errors
If an error occurs, errno is set to one of the following values:
EACCES CAUSE Either the calling process does not have search
permission to a component of pathname or does not
have read permission to the directory to be opened.
ACTION Make sure that the calling process has ACD traverse
directory (TD) access for all components of the
pathname and ACD read directory (RD) access to the
directory to be opened.
EFAULT CAUSE The system detected a NULL or bad address in
attempting to use the pathname parameter or the
pathname was not terminated by a null character.
ACTION Make sure that the pointer is correctly initialized.
EIMPL CAUSE The pathname begins with two slash characters (//).
ACTION Do not begin pathnames with two slash characters
(//).
EMFILE CAUSE The number of directory streams and files opened by
the calling process would exceed {OPEN_MAX}.
ACTION Reduce the number of directories and files opened by
the process.
ENAMETOOLONG CAUSE One of the following:
* The length of the pathname exceeds the
{PATH_MAX} limit (defined in the file
<limits.h>).
* A component of the pathname is longer than
{NAME_MAX} (defined in <limits.h>), and
{_POSIX_NO_TRUNC} is in effect for that
directory.
ACTION Make sure that both the component's length and the
full pathname length do not exceed the {NAME_MAX} or
{PATH_MAX} limits.
ENOENT CAUSE The specified directory does not exist, or pathname
points to an empty string.
ACTION Specify an existing directory name.
Table 4-0. (cont.)
ENOTDIR CAUSE A component of the pathname is not a directory.
ACTION Specify a valid pathname.
ESYSERR CAUSE An operating system error has occurred that does not
map directly to any of the above errors.
ACTION Examine the MPE/iX error stack for the type of system
error.
See Also
closedir(), readdir(), rewinddir(), <dirent.h>, POSIX.1 (Section 5.1.2)