| Standards / Extensions | C or C++ | Dependencies |
|---|---|---|
XPG4 |
both |
#define _XOPEN_SOURCE
#include <ftw.h>
int ftw(const char *path,
int (*fn)(const char *, const struct stat *, int),
int ndirs);If the integer is FTW_DNR, descendants of that directory will not be processed. If the integer is FTW_NS, the stat structure will contain undefined values. An example of an object that would cause FTW_NS to be passed to the function pointed to by fn would be a file in a directory with read but without execute (search) permission.
The ftw() function visits a directory before visiting any of its descendants.
The ftw() function uses at most one file descriptor for each level in the tree.
The argument ndirs should be in the range of 1 to OPEN_MAX.
The tree traversal continues until the tree is exhausted, an invocation of fn returns a nonzero value, or some other error, other than [EACCES], is detected within ftw().
The ndirs argument specifies the maximum number of directory streams or file descriptors or both available for use by ftw() while traversing the tree. When ftw() returns it closes any directory streams and file descriptors it uses not counting any opened by the application-supplied fn function.
Large file support for z/OS UNIX files: Large z/OS UNIX files are supported automatically for AMODE 64 C/C++ applications. AMODE 31 C/C++ applications must be compiled with the option LANGLVL(LONGLONG) and define the _LARGE_FILES feature test macro before any headers are included to enable this function to operate on z/OS UNIX files that are larger than 2 GB in size. File size and offset fields are enlarged to 63 bits in width. Therefore, any other function operating on the file is required to define the _LARGE_FILES feature test macro as well.
If the tree is exhausted, ftw() returns 0. If the function pointed to by fn returns a nonzero value, ftw() stops its tree traversal and returns whatever value was returned by the function pointed to by fn().