1READLINKAT(2)              Linux Programmer's Manual             READLINKAT(2)
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NAME

6       readlinkat - read value of a symbolic link relative to a directory file
7       descriptor
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SYNOPSIS

10       #include <fcntl.h> /* Definition of AT_* constants */
11       #include <unistd.h>
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13       int readlinkat(int dirfd, const char *pathname,
14                      char *buf, size_t bufsiz);
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16   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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18       readlinkat():
19           Since glibc 2.10:
20               _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
21           Before glibc 2.10:
22               _ATFILE_SOURCE
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DESCRIPTION

25       The readlinkat() system call operates in exactly the same way as  read‐
26       link(2), except for the differences described in this manual page.
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28       If  the  pathname given in pathname is relative, then it is interpreted
29       relative to the directory referred to  by  the  file  descriptor  dirfd
30       (rather  than  relative to the current working directory of the calling
31       process, as is done by readlink(2) for a relative pathname).
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33       If pathname is relative and dirfd is the special value  AT_FDCWD,  then
34       pathname  is  interpreted  relative to the current working directory of
35       the calling process (like readlink(2)).
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37       If pathname is absolute, then dirfd is ignored.
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39       Since Linux 2.6.39, pathname can be an empty string, in which case  the
40       call  operates  on  the  file referred to by dirfd (which may have been
41       obtained using the open(2) O_PATH flag).  In this case, dirfd can refer
42       to any type of file, not just a directory.
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RETURN VALUE

46       On success, readlinkat() returns the number of bytes placed in buf.  On
47       error, -1 is returned and errno is set to indicate the error.
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ERRORS

50       The same errors that occur for readlink(2) can  also  occur  for  read‐
51       linkat().  The following additional errors can occur for readlinkat():
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53       EBADF  dirfd is not a valid file descriptor.
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55       ENOTDIR
56              pathname is relative and dirfd is a file descriptor referring to
57              a file other than a directory.
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VERSIONS

60       readlinkat() was added to Linux in kernel 2.6.16; library  support  was
61       added to glibc in version 2.4.
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CONFORMING TO

64       POSIX.1-2008.
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NOTES

67       See openat(2) for an explanation of the need for readlinkat().
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SEE ALSO

70       openat(2), readlink(2), path_resolution(7)
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COLOPHON

73       This  page  is  part of release 3.53 of the Linux man-pages project.  A
74       description of the project, and information about reporting  bugs,  can
75       be found at http://www.kernel.org/doc/man-pages/.
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79Linux                             2013-07-31                     READLINKAT(2)
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