realpath(3c)

1realpath(3C)             Standard C Library Functions             realpath(3C)
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NAME

6       realpath - resolve pathname
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SYNOPSIS

9       #include <stdlib.h>
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11       char *realpath(const char *restrict file_name,
12            char *restrict resolved_name);
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DESCRIPTION

16       The  realpath()  function  derives,  from  the  pathname  pointed to by
17       file_name, an absolute pathname that names the same file, whose resolu‐
18       tion does not involve ".", "..", or symbolic links. The generated path‐
19       name is stored  as  a  null-terminated  string,  up  to  a  maximum  of
20       {PATH_MAX} bytes (defined in limits.h(3HEAD)), in the buffer pointed to
21       by resolved_name.
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RETURN VALUES

24       On successful completion, realpath() returns a pointer to the  resolved
25       name.   Otherwise,  realpath() returns a null pointer and sets errno to
26       indicate the error, and the  contents  of  the  buffer  pointed  to  by
27       resolved_name are left in an indeterminate state.
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ERRORS

30       The realpath() function will fail if:
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32       EACCES          Read or search permission was denied for a component of
33                       file_name.
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36       EINVAL          Either the file_name or  resolved_name  argument  is  a
37                       null pointer.
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40       EIO             An error occurred while reading from the file system.
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43       ELOOP           Too  many  symbolic links were encountered in resolving
44                       file_name.
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47       ELOOP           A loop exists in symbolic links encountered during res‐
48                       olution of the file_name argument.
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51       ENAMETOOLONG    The  file_name  argument is longer than {PATH_MAX} or a
52                       pathname component is longer than {NAME_MAX}.
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55       ENOENT          A component of file_name does not name an existing file
56                       or file_name points to an empty string.
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59       ENOTDIR         A component of the path prefix is not a directory.
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63       The realpath() function may fail if:
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65       ENAMETOOLONG    Pathname  resolution  of  a  symbolic  link produced an
66                       intermediate result whose length exceeds {PATH_MAX}.
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69       ENOMEM          Insufficient storage space is available.
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USAGE

73       The realpath() function operates on null-terminated strings.
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76       Execute permission is required for all the directories in the given and
77       the resolved path.
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80       The  realpath()  function might fail to return to the current directory
81       if an error occurs.
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ATTRIBUTES

84       See attributes(5) for descriptions of the following attributes:
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89       ┌─────────────────────────────┬─────────────────────────────┐
90       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
91       ├─────────────────────────────┼─────────────────────────────┤
92       │Interface Stability          │Standard                     │
93       ├─────────────────────────────┼─────────────────────────────┤
94       │MT-Level                     │MT-Safe                      │
95       └─────────────────────────────┴─────────────────────────────┘
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