1symlink(2) System Calls Manual symlink(2)
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6 symlink, symlinkat - make a new name for a file
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9 Standard C library (libc, -lc)
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12 #include <unistd.h>
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14 int symlink(const char *target, const char *linkpath);
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16 #include <fcntl.h> /* Definition of AT_* constants */
17 #include <unistd.h>
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19 int symlinkat(const char *target, int newdirfd, const char *linkpath);
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21 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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23 symlink():
24 _XOPEN_SOURCE >= 500 || _POSIX_C_SOURCE >= 200112L
25 || /* glibc <= 2.19: */ _BSD_SOURCE
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27 symlinkat():
28 Since glibc 2.10:
29 _POSIX_C_SOURCE >= 200809L
30 Before glibc 2.10:
31 _ATFILE_SOURCE
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34 symlink() creates a symbolic link named linkpath which contains the
35 string target.
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37 Symbolic links are interpreted at run time as if the contents of the
38 link had been substituted into the path being followed to find a file
39 or directory.
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41 Symbolic links may contain .. path components, which (if used at the
42 start of the link) refer to the parent directories of that in which the
43 link resides.
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45 A symbolic link (also known as a soft link) may point to an existing
46 file or to a nonexistent one; the latter case is known as a dangling
47 link.
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49 The permissions of a symbolic link are irrelevant; the ownership is ig‐
50 nored when following the link (except when the protected_symlinks fea‐
51 ture is enabled, as explained in proc(5)), but is checked when removal
52 or renaming of the link is requested and the link is in a directory
53 with the sticky bit (S_ISVTX) set.
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55 If linkpath exists, it will not be overwritten.
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57 symlinkat()
58 The symlinkat() system call operates in exactly the same way as sym‐
59 link(), except for the differences described here.
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61 If the pathname given in linkpath is relative, then it is interpreted
62 relative to the directory referred to by the file descriptor newdirfd
63 (rather than relative to the current working directory of the calling
64 process, as is done by symlink() for a relative pathname).
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66 If linkpath is relative and newdirfd is the special value AT_FDCWD,
67 then linkpath is interpreted relative to the current working directory
68 of the calling process (like symlink()).
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70 If linkpath is absolute, then newdirfd is ignored.
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72 See openat(2) for an explanation of the need for symlinkat().
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75 On success, zero is returned. On error, -1 is returned, and errno is
76 set to indicate the error.
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79 EACCES Write access to the directory containing linkpath is denied, or
80 one of the directories in the path prefix of linkpath did not
81 allow search permission. (See also path_resolution(7).)
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83 EBADF (symlinkat()) linkpath is relative but newdirfd is neither
84 AT_FDCWD nor a valid file descriptor.
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86 EDQUOT The user's quota of resources on the filesystem has been ex‐
87 hausted. The resources could be inodes or disk blocks, depend‐
88 ing on the filesystem implementation.
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90 EEXIST linkpath already exists.
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92 EFAULT target or linkpath points outside your accessible address space.
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94 EIO An I/O error occurred.
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96 ELOOP Too many symbolic links were encountered in resolving linkpath.
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98 ENAMETOOLONG
99 target or linkpath was too long.
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101 ENOENT A directory component in linkpath does not exist or is a dan‐
102 gling symbolic link, or target or linkpath is an empty string.
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104 ENOENT (symlinkat()) linkpath is a relative pathname and newdirfd
105 refers to a directory that has been deleted.
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107 ENOMEM Insufficient kernel memory was available.
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109 ENOSPC The device containing the file has no room for the new directory
110 entry.
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112 ENOTDIR
113 A component used as a directory in linkpath is not, in fact, a
114 directory.
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116 ENOTDIR
117 (symlinkat()) linkpath is relative and newdirfd is a file de‐
118 scriptor referring to a file other than a directory.
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120 EPERM The filesystem containing linkpath does not support the creation
121 of symbolic links.
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123 EROFS linkpath is on a read-only filesystem.
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126 POSIX.1-2008.
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129 symlink()
130 SVr4, 4.3BSD, POSIX.1-2001.
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132 symlinkat()
133 POSIX.1-2008. Linux 2.6.16, glibc 2.4.
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135 glibc notes
136 On older kernels where symlinkat() is unavailable, the glibc wrapper
137 function falls back to the use of symlink(). When linkpath is a rela‐
138 tive pathname, glibc constructs a pathname based on the symbolic link
139 in /proc/self/fd that corresponds to the newdirfd argument.
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142 No checking of target is done.
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144 Deleting the name referred to by a symbolic link will actually delete
145 the file (unless it also has other hard links). If this behavior is
146 not desired, use link(2).
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149 ln(1), namei(1), lchown(2), link(2), lstat(2), open(2), readlink(2),
150 rename(2), unlink(2), path_resolution(7), symlink(7)
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154Linux man-pages 6.04 2023-03-30 symlink(2)