man3/scandirat.3

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.TH SCANDIRAT 3 2012-03-17 "Linux" "Linux Programmer's Manual"
.SH NAME
scandirat \- scan a directory relative to a directory file descriptor
.SH SYNOPSIS
.nf
.BR "#define _GNU_SOURCE" "         /* See feature_test_macros(7) */"

.BR "#include <fcntl.h>" "          /* Definition of AT_* constants */"
.B #include <dirent.h>
.sp
.fi
.BI "int scandirat(int " dirfd ", const char *" dirp ","
.BI "struct dirent ***" namelist ,
.nf
.RS
.BI "int (*" filter ")(const struct dirent *),"
.BI "int (*" compar ")(const struct dirent **, const struct dirent **));"
.RE
.fi
.SH DESCRIPTION
The
.BR scandirat ()
system call operates in exactly the same way as
.BR scandir (3),
except for the differences described in this manual page.

If the pathname given in
.I dirp
is relative, then it is interpreted relative to the directory
referred to by the file descriptor
.I dirfd
(rather than relative to the current working directory of
the calling process, as is done by
.BR scandir (3)
for a relative pathname).

If
.I dirp
is relative and
.I dirfd
is the special value
.BR AT_FDCWD ,
then
.I dirp
is interpreted relative to the current working
directory of the calling process (like
.BR scandir (3)).

If
.I dirp
is absolute, then
.I dirfd
is ignored.
.SH "RETURN VALUE"
On success,
.BR scandirat ()
returns the number of directory entries selected.
On error, \-1 is returned and
.I errno
is set to indicate the error.
.SH ERRORS
The same errors that occur for
.BR scandir (3)
can also occur for
.BR scandirat ().
The following additional errors can occur for
.BR scandirat ():
.TP
.B EBADF
.I dirfd
is not a valid file descriptor.
.TP
.B ENOTDIR
.I dirp
is a relative path and
.I dirfd
is a file descriptor referring to a file other than a directory.
.SH VERSIONS
.BR scandirat ()
was added to glibc in version 2.15.
.SH "CONFORMING TO"
This function is a GNU extension.
.SH NOTES
See
.BR openat (2)
for an explanation of the need for
.BR scandirat ().
.SH "SEE ALSO"
.BR openat (2),
.BR scandir (3),
.BR path_resolution (7)