2004-11-03 13:51:07 +00:00
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.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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2007-06-20 22:33:04 +00:00
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.TH "REALPATH" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.\" realpath
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2007-09-20 06:03:25 +00:00
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.SH PROLOG
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This manual page is part of the POSIX Programmer's Manual.
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The Linux implementation of this interface may differ (consult
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the corresponding Linux manual page for details of Linux behavior),
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or the interface may not be implemented on Linux.
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2004-11-03 13:51:07 +00:00
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.SH NAME
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realpath \- resolve a pathname
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.SH SYNOPSIS
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.LP
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\fB#include <stdlib.h>
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.br
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.sp
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char *realpath(const char *restrict\fP \fIfile_name\fP\fB,
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.br
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\ \ \ \ \ \ char *restrict\fP \fIresolved_name\fP\fB); \fP
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\fB
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.br
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\fP
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.SH DESCRIPTION
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.LP
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The \fIrealpath\fP() function shall derive, from the pathname pointed
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to by \fIfile_name\fP, an absolute pathname that names
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the same file, whose resolution does not involve \fB'.'\fP , \fB'..'\fP
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, or symbolic links. The generated pathname shall be
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stored as a null-terminated string, up to a maximum of {PATH_MAX}
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bytes, in the buffer pointed to by \fIresolved_name\fP.
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.LP
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If \fIresolved_name\fP is a null pointer, the behavior of \fIrealpath\fP()
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is implementation-defined.
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.SH RETURN VALUE
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.LP
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Upon successful completion, \fIrealpath\fP() shall return a pointer
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to the resolved name. Otherwise, \fIrealpath\fP() shall
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return a null pointer and set \fIerrno\fP to indicate the error, and
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the contents of the buffer pointed to by \fIresolved_name\fP
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are undefined.
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.SH ERRORS
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.LP
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The \fIrealpath\fP() function shall fail if:
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.TP 7
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.B EACCES
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Read or search permission was denied for a component of \fIfile_name\fP.
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.TP 7
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.B EINVAL
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The \fIfile_name\fP argument is a null pointer.
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.TP 7
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.B EIO
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An error occurred while reading from the file system.
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.TP 7
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.B ELOOP
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A loop exists in symbolic links encountered during resolution of the
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\fIpath\fP argument.
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.TP 7
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.B ENAMETOOLONG
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The length of the \fIfile_name\fP argument exceeds {PATH_MAX} or a
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pathname component is longer than {NAME_MAX}.
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.TP 7
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.B ENOENT
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A component of \fIfile_name\fP does not name an existing file or \fIfile_name\fP
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points to an empty string.
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.TP 7
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.B ENOTDIR
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A component of the path prefix is not a directory.
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.sp
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.LP
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The \fIrealpath\fP() function may fail if:
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.TP 7
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.B ELOOP
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More than {SYMLOOP_MAX} symbolic links were encountered during resolution
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of the \fIpath\fP argument.
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.TP 7
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.B ENAMETOOLONG
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Pathname resolution of a symbolic link produced an intermediate result
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whose length exceeds {PATH_MAX}.
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.TP 7
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.B ENOMEM
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Insufficient storage space is available.
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.sp
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.SS Generating an Absolute Pathname
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.LP
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The following example generates an absolute pathname for the file
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identified by the \fIsymlinkpath\fP argument. The generated
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pathname is stored in the \fIactualpath\fP array.
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.sp
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.RS
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.nf
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\fB#include <stdlib.h>
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\&...
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char *symlinkpath = "/tmp/symlink/file";
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char actualpath [PATH_MAX+1];
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char *ptr;
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.sp
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ptr = realpath(symlinkpath, actualpath);
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\fP
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.fi
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.RE
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.SH APPLICATION USAGE
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.LP
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None.
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.SH RATIONALE
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.LP
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Since the maximum pathname length is arbitrary unless {PATH_MAX} is
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defined, an application generally cannot supply a
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\fIresolved_name\fP buffer with size {{PATH_MAX}+1}.
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.SH FUTURE DIRECTIONS
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.LP
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In the future, passing a null pointer to \fIrealpath\fP() for the
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\fIresolved_name\fP argument may be defined to have
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\fIrealpath\fP() allocate space for the generated pathname.
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.SH SEE ALSO
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.LP
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\fIgetcwd\fP() , \fIsysconf\fP() , the Base Definitions volume of
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IEEE\ Std\ 1003.1-2001, \fI<stdlib.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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