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opendir(3) [bsd man page]

DIRECTORY(3)						     Library Functions Manual						      DIRECTORY(3)

NAME
opendir, readdir, telldir, seekdir, rewinddir, closedir - directory operations SYNOPSIS
#include <sys/types.h> #include <sys/dir.h> DIR *opendir(filename) char *filename; struct direct *readdir(dirp) DIR *dirp; long telldir(dirp) DIR *dirp; seekdir(dirp, loc) DIR *dirp; long loc; rewinddir(dirp) DIR *dirp; closedir(dirp) DIR *dirp; DESCRIPTION
Opendir opens the directory named by filename and associates a directory stream with it. Opendir returns a pointer to be used to identify the directory stream in subsequent operations. The pointer NULL is returned if filename cannot be accessed, or if it cannot malloc(3) enough memory to hold the whole thing. Readdir returns a pointer to the next directory entry. It returns NULL upon reaching the end of the directory or detecting an invalid seekdir operation. Telldir returns the current location associated with the named directory stream. Seekdir sets the position of the next readdir operation on the directory stream. The new position reverts to the one associated with the directory stream when the telldir operation was performed. Values returned by telldir are good only for the lifetime of the DIR pointer from which they are derived. If the directory is closed and then reopened, the telldir value may be invalidated due to undetected direc- tory compaction. It is safe to use a previous telldir value immediately after a call to opendir and before any calls to readdir. Rewinddir resets the position of the named directory stream to the beginning of the directory. Closedir closes the named directory stream and frees the structure associated with the DIR pointer. Sample code which searchs a directory for entry ``name'' is: len = strlen(name); dirp = opendir("."); for (dp = readdir(dirp); dp != NULL; dp = readdir(dirp)) if (dp->d_namlen == len && !strcmp(dp->d_name, name)) { closedir(dirp); return FOUND; } closedir(dirp); return NOT_FOUND; SEE ALSO
open(2), close(2), read(2), lseek(2), dir(5) 4.2 Berkeley Distribution September 24, 1985 DIRECTORY(3)

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DIRECTORY(3)						   BSD Library Functions Manual 					      DIRECTORY(3)

NAME
closedir, dirfd, opendir, readdir, readdir_r, rewinddir, seekdir, telldir -- directory operations LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <dirent.h> int closedir(DIR *dirp); int dirfd(DIR *dirp); DIR * opendir(const char *dirname); struct dirent * readdir(DIR *dirp); int readdir_r(DIR *restrict dirp, struct dirent *restrict entry, struct dirent **restrict result); void rewinddir(DIR *dirp); void seekdir(DIR *dirp, long loc); long telldir(DIR *dirp); DESCRIPTION
The opendir() function opens the directory named by dirname, associates a directory stream with it, and returns a pointer to be used to iden- tify the directory stream in subsequent operations. The pointer NULL is returned if dirname cannot be accessed or if it cannot malloc(3) enough memory to hold the whole thing. The readdir() function returns a pointer to the next directory entry. It returns NULL upon reaching the end of the directory or detecting an invalid seekdir() operation. readdir_r() provides the same functionality as readdir(), but the caller must provide a directory entry buffer to store the results in. If the read succeeds, result is pointed at the entry; upon reaching the end of the directory, result is set to NULL. readdir_r() returns 0 on success or an error number to indicate failure. The telldir() function returns the current location associated with the named directory stream. Values returned by telldir() are good only for the lifetime of the DIR pointer (e.g., dirp) from which they are derived. If the directory is closed and then reopened, prior values returned by telldir() will no longer be valid. The seekdir() function sets the position of the next readdir() operation on the directory stream. The new position reverts to the one asso- ciated with the directory stream when the telldir() operation was performed. The rewinddir() function resets the position of the named directory stream to the beginning of the directory. The closedir() function closes the named directory stream and frees the structure associated with the dirp pointer, returning 0 on success. On failure, -1 is returned and the global variable errno is set to indicate the error. The dirfd() function returns the integer file descriptor associated with the named directory stream, see open(2). Sample code which searches a directory for entry ``name'' is: len = strlen(name); dirp = opendir("."); while ((dp = readdir(dirp)) != NULL) if (dp->d_namlen == len && !strcmp(dp->d_name, name)) { (void)closedir(dirp); return FOUND; } (void)closedir(dirp); return NOT_FOUND; LEGACY SYNOPSIS
#include <sys/types.h> #include <dirent.h> <sys/types.h> is necessary for these functions. SEE ALSO
close(2), lseek(2), open(2), read(2), compat(5), dir(5) HISTORY
The closedir(), dirfd(), opendir(), readdir(), rewinddir(), seekdir(), and telldir() functions appeared in 4.2BSD. BSD
June 4, 1993 BSD
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