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