b13f3212ad
see the reference here: https://pubs.opengroup.org/onlinepubs/009695399/basedefs/ftw.h.html Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com> Change-Id: I3b368106a56b0e9d4c653f3ae16304b0a9d55fbc
223 lines
9.1 KiB
C
223 lines
9.1 KiB
C
/****************************************************************************
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* include/ftw.h
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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#ifndef __INCLUDE_FTW_H
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#define __INCLUDE_FTW_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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/* The <ftw.h> header defines the stat structure and the symbolic names for
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* st_mode and the file type test macros as described in sys/stat.h.
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*
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* Inclusion of the <ftw.h> header may also make visible all symbols from
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* sys/stat.h.
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*/
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#include <sys/stat.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Macros for use as values of the third argument to the application-supplied
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* function that is passed as the second argument to ftw() and nftw():
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*/
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#define FTW_F 0 /* File */
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#define FTW_D 1 /* Directory */
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#define FTW_DNR 2 /* Directory without read permission */
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#define FTW_DP 3 /* Directory with subdirectories visited */
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#define FTW_NS 4 /* Unknown type; stat() failed */
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#define FTW_SL 5 /* Symbolic link */
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#define FTW_SLN 6 /* Symbolic link that names a nonexistent file */
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/* Macros for use as values of the fourth argument to nftw() */
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#define FTW_PHYS 1 /* Physical walk, does not follow symbolic links.
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* Otherwise, nftw() follows links but does not walk
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* down any path that crosses itself. */
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#define FTW_MOUNT 2 /* The walk does not cross a mount point. */
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#define FTW_DEPTH 4 /* All subdirectories are visited before the directory
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* itself. */
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#ifndef CONFIG_DISABLE_ENVIRON
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#define FTW_CHDIR 8 /* The walk changes to each directory before reading
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* it. */
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#endif
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/* The fourth argument of the ftw/nftw callback is a pointer to an FTW
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* structure. The value of base is the offset of the object's filename in
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* the pathname passed as the first argument to the callback. The value of
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* level indicates depth relative to the root of the walk, where the root
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* level is 0.
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*/
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struct FTW
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{
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int base; /* Offset of object's filename in the pathname */
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int level; /* Depth relative to the root of the walk */
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};
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/* This is the type of the ftw callback */
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typedef int (*ftw_cb_t)(FAR const char *path, FAR const struct stat *buf,
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int info);
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/* This is the type of the nftw callback */
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typedef int (*nftw_cb_t)(FAR const char *path, FAR const struct stat *buf,
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int info, FAR struct FTW *pftw);
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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#ifdef __cplusplus
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#define EXTERN extern "C"
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extern "C"
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{
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#else
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#define EXTERN extern
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#endif
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/****************************************************************************
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* Name: ftw
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*
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* Description:
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* The ftw() function will recursively descend the directory hierarchy
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* rooted in 'path'. For each object in the hierarchy, ftw() will call
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* the function pointed to by 'fn', passing it a pointer to a null-
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* terminated character string containing the name of the object, a
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* pointer to a stat structure containing information about the object,
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* and an integer that characterizes object.
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*
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* The ftw() function will visit a directory before visiting any of its
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* descendants.
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*
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* The ftw() function will use at most one file descriptor for each level
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* in the tree.
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*
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* The tree traversal will continue until either the tree is exhausted, an
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* invocation of 'fn' returns a non-zero value, or some error, other than
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* EACCES, is detected within ftw().
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*
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* When ftw() returns it will close any directory streams and file
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* descriptors it uses not counting any opened by the application-supplied
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* 'fn' function.
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*
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* The results are unspecified if the application-supplied 'fn' function
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* does not preserve the current working directory.
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*
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* The ftw() function need not be reentrant. A function that is not
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* required to be reentrant is not required to be thread-safe.
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*
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* Input Parameters:
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* path - The 'root' of the directory hierarchy to descend
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* fn - The callback function to be invoked as each object in the
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* heirarchy is encountered.
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* fdlimit - The fdlimit argument specifies the maximum number of directory
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* streams or file descriptors or both available for use by ftw()
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* while traversing the tree.The maximum depth of the directories
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* to visit. The fdlimit argument should be in the range [1,
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* {OPEN_MAX}].
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*
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* Returned Value:
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* If the tree is exhausted, ftw() will return 0. If the function pointed
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* to by fn returns a non-zero value, ftw() will stop its tree traversal
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* and return whatever value was returned by the function pointed to by
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* 'fn'. If ftw() detects an error, it will return -1 and set errno to
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* indicate the error.
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*
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* If ftw() encounters an error other than EACCES (see FTW_DNR and FTW_NS),
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* it will return -1 and set errno to indicate the error. The external
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* variable errno may contain any error value that is possible when a
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* directory is opened or when one of the stat functions is executed on a
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* directory or file.
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*
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****************************************************************************/
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int ftw(FAR const char *path, ftw_cb_t fn, int fdlimit);
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/****************************************************************************
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* Name: nftw
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*
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* Description:
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* The nftw() function will recursively descend the directory hierarchy
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* rooted in 'path'. The nftw() function has a similar effect to ftw()
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* except that it takes an additional argument 'flags'
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*
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* Input Parameters:
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*
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* path - The 'root' of the directory hierarchy to descend
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* fn - The callback function to be invoked as each object in the
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* heirarchy is encountered.
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* fdlimit - The fdlimit argument specifies the maximum number of directory
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* streams or file descriptors or both available for use by
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* nftw() while traversing the tree.The maximum depth of the
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* directories to visit. The fdlimit argument should be in the
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* range [1, {OPEN_MAX}].
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* flags - A bitwise-inclusive OR of zero or more of the following flags:
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*
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* FTW_CHDIR
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* If set, nftw() will change the current working directory to each
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* directory as it reports files in that directory. If clear, nftw()
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* will not change the current working directory.
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* FTW_DEPTH
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* If set, nftw() will report all files in a directory before
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* reporting the directory itself. If clear, nftw() will report any
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* directory before reporting the files in that directory.
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* FTW_MOUNT
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* If set, nftw() will only report files in the same file system as
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* path. If clear, nftw() will report all files encountered during
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* the walk.
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* FTW_PHYS
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* If set, nftw() will perform a physical walk and will not follow
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* symbolic links.
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*
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* Returned Value:
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* If the tree is exhausted, nftw() will return 0. If the function pointed
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* to by fn returns a non-zero value, nftw() will stop its tree traversal
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* and return whatever value was returned by the function pointed to by
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* 'fn'. If nftw() detects an error, it will return -1 and set errno to
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* indicate the error.
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*
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* If nftw() encounters an error other than EACCES (see FTW_DNR and
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* FTW_NS), it will return -1 and set errno to indicate the error. The
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* external variable errno may contain any error value that is possible
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* when a directory is opened or when one of the stat functions is
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* executed on a directory or file.
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*
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*
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****************************************************************************/
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int nftw(FAR const char *path, nftw_cb_t fn, int fdlimit, int flags);
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#undef EXTERN
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#ifdef __cplusplus
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}
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#endif
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#endif /* __INCLUDE_FTW_H */
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