diff options
Diffstat (limited to 'lib/libc/gen/directory.3')
| -rw-r--r-- | lib/libc/gen/directory.3 | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/lib/libc/gen/directory.3 b/lib/libc/gen/directory.3 new file mode 100644 index 0000000..0503989 --- /dev/null +++ b/lib/libc/gen/directory.3 @@ -0,0 +1,183 @@ +.\" Copyright (c) 1983, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)directory.3 8.1 (Berkeley) 6/4/93 +.\" +.Dd June 4, 1993 +.Dt DIRECTORY 3 +.Os BSD 4.2 +.Sh NAME +.Nm opendir , +.Nm readdir , +.Nm telldir , +.Nm seekdir , +.Nm rewinddir , +.Nm closedir , +.Nm dirfd +.Nd directory operations +.Sh SYNOPSIS +.Fd #include <sys/types.h> +.Fd #include <dirent.h> +.Ft DIR * +.Fn opendir "const char *filename" +.Ft struct dirent * +.Fn readdir "DIR *dirp" +.Ft long +.Fn telldir "const DIR *dirp" +.Ft void +.Fn seekdir "DIR *dirp" "long loc" +.Ft void +.Fn rewinddir "DIR *dirp" +.Ft int +.Fn closedir "DIR *dirp" +.Ft int +.Fn dirfd "DIR *dirp" +.Sh DESCRIPTION +The +.Fn opendir +function +opens the directory named by +.Fa filename , +associates a +.Em directory stream +with it +and +returns a pointer to be used to identify the +.Em directory stream +in subsequent operations. The pointer +.Dv NULL +is returned if +.Fa filename +cannot be accessed, or if it cannot +.Xr malloc 3 +enough memory to hold the whole thing. +.Pp +The +.Fn readdir +function +returns a pointer to the next directory entry. It returns +.Dv NULL +upon reaching the end of the directory or detecting an invalid +.Fn seekdir +operation. +.Pp +The +.Fn telldir +function +returns the current location associated with the named +.Em directory stream . +.Pp +The +.Fn seekdir +function +sets the position of the next +.Fn readdir +operation on the +.Em directory stream . +The new position reverts to the one associated with the +.Em directory stream +when the +.Fn telldir +operation was performed. Values returned by +.Fn telldir +are good only for the lifetime of the +.Dv DIR +pointer, +.Fa dirp , +from which they are derived. +If the directory is closed and then reopened, the +.Fn telldir +value may be invalidated due to undetected directory compaction. +It is safe to use a previous +.Fn telldir +value immediately after a call to +.Fn opendir +and before any calls to +.Fn readdir . +.Pp +The +.Fn rewinddir +function +resets the position of the named +.Em directory stream +to the beginning of the directory. +.Pp +The +.Fn closedir +function +closes the named +.Em directory stream +and frees the structure associated with the +.Fa dirp +pointer, +returning 0 on success. +On failure, \-1 is returned and the global variable +.Va errno +is set to indicate the error. +.Pp +The +.Fn dirfd +function +returns the integer file descriptor associated with the named +.Em directory stream , +see +.Xr open 2 . +.Pp +Sample code which searchs a directory for entry ``name'' is: +.Bd -literal -offset indent +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; +.Ed +.Sh SEE ALSO +.Xr open 2 , +.Xr close 2 , +.Xr read 2 , +.Xr lseek 2 , +.Xr dir 5 +.Sh HISTORY +The +.Fn opendir , +.Fn readdir , +.Fn telldir , +.Fn seekdir , +.Fn rewinddir , +.Fn closedir , +and +.Fn dirfd +functions appeared in +.Bx 4.2 . |
