Standards
| Standards / Extensions |
C or C++ |
Dependencies |
|---|
z/OS® UNIX
|
both |
OS/390 V2R6 |
Format
#define _OPEN_SYS_DIR_EXT
#include <dirent.h>
DIR *__opendir2(const char *dirname, size_t bufsize);
General description
Opens a directory so
that it can be read with readdir() or __readdir2(). The first readdir()
or __readdir2() call reads the first entry in the directory.
dirname is
a string giving the name of the directory you want to open. bufsize is
the size (in bytes) of the internal work buffer used by readdir()
or __readdir2() to hold directory entries. The larger the buffer,
the less overhead there will be when reading through large numbers
of directory entries. This buffer will exist until the directory
is closed. If the specified buffer size is too small, it is ignored.
A minimum-size buffer is used instead.
__opendir2() is the
same as opendir(), except that the buffer size can be specified as
a parameter.
Returned value
If successful, __opendir2()
returns a pointer to a DIR object. This object describes
the directory and is used in subsequent operations on the directory,
in the same way that FILE objects are used in file
I/O operations.
If unsuccessful, __opendir2() returns a NULL
pointer and sets errno to one of the following values:
- Error Code
- Description
- EACCES
- The process does not have permission to search some component
of dirname, or it does not have read permission
on the directory itself.
- ELOOP
- A loop exists in the symbolic links. This error is issued if
more than POSIX_SYMLOOP (defined in the limits.h header file) symbolic
links are encountered during resolution of the dirname argument.
- EMFILE
- The process has too many other file descriptors already open.
- ENAMETOOLONG
- dirname is longer than PATH_MAX characters,
or some component of dirname is longer than
NAME_MAX characters while _POSIX_NO_TRUNC is in effect.
For symbolic links, the length of the pathname string substituted
for a symbolic link exceeds PATH_MAX. The PATH_MAX and NAME_MAX values
can be determined using pathconf().
- ENFILE
- The entire system has too many other file descriptors already
open.
- ENOENT
- The directory dirname does not exist.
- ENOMEM
- There is not enough storage available to open the directory using
a buffer that is length bufsize bytes long.
- ENOTDIR
- Some component of the dirname pathname
is not a directory.