Open System Services Library Calls Reference Manual (G06.29+, H06.08+, J06.03+)

OSS Library Calls (n - r) readdir(3)
NAME
readdir - Reads a directory stream
LIBRARY
G-series native OSS processes: /G/system/sysnn/zossfsrl
32-bit H-series and J-series OSS processes: /G/system/zdllnnn/zossfdll |
64-bit H-series and J-series OSS processes: /G/system/zdllnnn/yossfdll |
SYNOPSIS
#include <sys/types.h> /* optional except for POSIX.1 */
#include <dirent.h>
struct dirent *readdir(
DIR *dir_pointer);
PARAMETERS
dir_pointer Points to the dir structure of an open directory.
DESCRIPTION
The type DIR, which is defined in the dirent.h header file, represents a directory stream, which
is an ordered sequence of all the directory entries in a particular directory. (Directory streams are
not implemented through file descriptors.) The structure pointed to by the dir_pointer parameter
is established by a prior call to the opendir( ) function.
The readdir( ) function returns a pointer to a structure representing the directory entry at the
current position in the directory stream specified by the dir_pointer parameter, and then positions
the directory stream at the next entry. readdir() returns a null pointer upon reaching the end of
the directory stream but does not change the value of errno. The dirent structure defined in the
dirent.h header file describes a directory entry.
The readdir( ) function does not return directory entries containing empty names. If entries for .
(dot) or ..(dot-dot) exist, one entry is returned for . (dot) and one entry is returned for ..(dot-dot);
otherwise, they are not returned.
The pointer returned by the readdir( ) function points to data that can be overwritten (or data that
is contained in a buffer that can be freed) by another call to readdir( ) on the same directory
stream. This data is available until another readdir( ) or closedir( ) call is made on the same
directory stream.
When one of the set of exec, tdm_exec,ortdm_spawn functions is called, all open directory
streams are closed automatically. (For calls by tdm_spawn functions, only the directory streams
of the child process are closed.) The effect is the same as if the closedir( ) function had been
called for each open directory stream.
If the dir_pointer parameter does not refer to a currently opened directory stream when it is
passed to the readdir( ) function, the following can occur:
• The error value [EBADF] or [EFAULT] might be returned.
• The caller might receive a SIGSEGV or SIGILL signal in the OSS environment.
• The caller might cause a trap condition in the Guardian environment.
• User memory might be corrupted.
When the readdir() function is called from 64-bit OSS processes, files larger than approximately |
2 gigabytes are supported. However, for 32-bit OSS processes to access these larger files, the |
application must be compiled using the #define _LARGEFILE64_SOURCE 1 feature test |
macro or an equivalent compiler directive.
527187-017 Hewlett-Packard Company 5−137