Content-type: text/html Man page of readlink

readlink

Section: System Calls (2)
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NAME

readlink - Reads the value of a symbolic link  

SYNOPSIS

#include <unistd.h>

int readlink (
        const char *path,
        char *buffer,
        size_t buf_size);

The following version of the buf_size argument does not conform to current standards and is supported only for backward compatibility:


        int buf_size  

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

readlink():  XPG4-UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags.  

PARAMETERS

Specifies the pathname of the destination file or directory. Points to the user's buffer. The buffer should be at least as large as the buf_size parameter. Specifies the size of the buffer.  

DESCRIPTION

The readlink() function places the contents of the symbolic link named by the path parameter in buffer, which has size buf_size.

If the actual length of the symbolic link is greater than buf_size, an error is returned. The length of a symbolic link will not exceed PATH_MAX.

[Digital]  If the actual length of the symbolic link is less than buf_size, the string copied into the buffer is null-terminated.

For a readlink() function to complete successfully, the calling process must have search access to the directory containing the link.  

RETURN VALUES

Upon successful completion, the readlink() function returns a count of bytes placed in the buffer (not including any terminating null). If the readlink() function fails, the buffer is not modified, a value of -1 is returned, and errno is set to indicate the error.  

ERRORS

The readlink() function sets errno to the specified values for the following conditions:

Search permission is denied on a component of the path prefix of the path parameter, or read permission is denied on the final component of the path prefix of the path parameter. The file named by the path parameter is not a symbolic link. An I/O error occurred while reading from or writing to the file system. Too many symbolic links were encountered in resolving path. The length of the path parameter exceeds PATH_MAX, or a pathname component is longer than NAME_MAX while {_POSIX_NO_TRUNC} is in effect. The file named by the path parameter does not exist or the path parameter points to an empty string. A component of the path prefix of the path parameter is not a directory. [Digital]  The pathname in the symbolic link is longer than buf_size.

For NFS file access, if the readlink() function fails, errno may also be set to one of the following values: [Digital]  The owner or group ID is not a value supported by this implementation. [Digital]  Indicates a stale NFS file handle. An opened file was deleted by the server or another client; a client cannot open a file because the server has unmounted or unexported the remote directory; or the directory that contains an opened file was either unmounted or unexported by the server.  

RELATED INFORMATION

Functions: link(2), stat(2), symlink(2), unlink(2)

Standards: standards(5) delim off


 

Index

NAME
SYNOPSIS
STANDARDS
PARAMETERS
DESCRIPTION
RETURN VALUES
ERRORS
RELATED INFORMATION

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Time: 02:40:14 GMT, October 02, 2010