from small one page howto to huge articles all in one place
 

search text in:





Poll
Which kernel version do you use?





poll results

Last additions:
using iotop to find disk usage hogs

using iotop to find disk usage hogs

words:

887

views:

85751

userrating:

average rating: 1.7 (82 votes) (1=very good 6=terrible)


May 25th. 2007:
Words

486

Views

202177

why adblockers are bad


Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

words:

161

views:

84184

userrating:

average rating: 1.3 (27 votes) (1=very good 6=terrible)


April, 26th. 2006:

Druckversion
You are here: manpages





GETCWD

Section: Linux Programmer's Manual (3)
Updated: 2015-03-02
Index Return to Main Contents
 

NAME

getcwd, getwd, get_current_dir_name - get current working directory  

SYNOPSIS

#include <unistd.h>

char *getcwd(char *buf, size_t size);

char *getwd(char *buf);

char *get_current_dir_name(void);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

get_current_dir_name():

_GNU_SOURCE

getwd():

Since glibc 2.12:
_BSD_SOURCE ||
    (_XOPEN_SOURCE >= 500 ||
        _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) &&
    !(_POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700)
Before glibc 2.12: _BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
 

DESCRIPTION

These functions return a null-terminated string containing an absolute pathname that is the current working directory of the calling process. The pathname is returned as the function result and via the argument buf, if present.

The getcwd() function copies an absolute pathname of the current working directory to the array pointed to by buf, which is of length size.

If the length of the absolute pathname of the current working directory, including the terminating null byte, exceeds size bytes, NULL is returned, and errno is set to ERANGE; an application should check for this error, and allocate a larger buffer if necessary.

As an extension to the POSIX.1-2001 standard, glibc's getcwd() allocates the buffer dynamically using malloc(3) if buf is NULL. In this case, the allocated buffer has the length size unless size is zero, when buf is allocated as big as necessary. The caller should free(3) the returned buffer.

get_current_dir_name() will malloc(3) an array big enough to hold the absolute pathname of the current working directory. If the environment variable PWD is set, and its value is correct, then that value will be returned. The caller should free(3) the returned buffer.

getwd() does not malloc(3) any memory. The buf argument should be a pointer to an array at least PATH_MAX bytes long. If the length of the absolute pathname of the current working directory, including the terminating null byte, exceeds PATH_MAX bytes, NULL is returned, and errno is set to ENAMETOOLONG. (Note that on some systems, PATH_MAX may not be a compile-time constant; furthermore, its value may depend on the filesystem, see pathconf(3).) For portability and security reasons, use of getwd() is deprecated.  

RETURN VALUE

On success, these functions return a pointer to a string containing the pathname of the current working directory. In the case getcwd() and getwd() this is the same value as buf.

On failure, these functions return NULL, and errno is set to indicate the error. The contents of the array pointed to by buf are undefined on error.  

ERRORS

EACCES
Permission to read or search a component of the filename was denied.
EFAULT
buf points to a bad address.
EINVAL
The size argument is zero and buf is not a null pointer.
EINVAL
getwd(): buf is NULL.
ENAMETOOLONG
getwd(): The size of the null-terminated absolute pathname string exceeds PATH_MAX bytes.
ENOENT
The current working directory has been unlinked.
ERANGE
The size argument is less than the length of the absolute pathname of the working directory, including the terminating null byte. You need to allocate a bigger array and try again.
 

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).
InterfaceAttributeValue
getcwd(), getwd() Thread safetyMT-Safe
get_current_dir_name() Thread safetyMT-Safe env
 

CONFORMING TO

getcwd() conforms to POSIX.1-2001. Note however that POSIX.1-2001 leaves the behavior of getcwd() unspecified if buf is NULL.

getwd() is present in POSIX.1-2001, but marked LEGACY. POSIX.1-2008 removes the specification of getwd(). Use getcwd() instead. POSIX.1-2001 does not define any errors for getwd().

get_current_dir_name() is a GNU extension.  

NOTES

Under Linux, the function getcwd() is a system call (since 2.1.92). On older systems it would query /proc/self/cwd. If both system call and proc filesystem are missing, a generic implementation is called. Only in that case can these calls fail under Linux with EACCES.

These functions are often used to save the location of the current working directory for the purpose of returning to it later. Opening the current directory (".") and calling fchdir(2) to return is usually a faster and more reliable alternative when sufficiently many file descriptors are available, especially on platforms other than Linux.  

SEE ALSO

chdir(2), fchdir(2), open(2), unlink(2), free(3), malloc(3)  

COLOPHON

This page is part of release 3.81 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at http://www.kernel.org/doc/man-pages/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
CONFORMING TO
NOTES
SEE ALSO
COLOPHON


Please read "Why adblockers are bad".



Other free services
toURL.org
Shorten long
URLs to short
links like
http://tourl.org/2
tourl.org
.
Reverse DNS lookup
Find out which hostname(s)
resolve to a
given IP or other hostnames for the server
www.reversednslookup.org
rdf newsfeed | rss newsfeed | Atom newsfeed
- Powered by LeopardCMS - Running on Gentoo -
Copyright 2004-2013 Sascha Nitsch Unternehmensberatung UG(haftungsbeschränkt)
Valid XHTML1.1 : Valid CSS : buttonmaker
- Level Triple-A Conformance to Web Content Accessibility Guidelines 1.0 -
- Copyright and legal notices -
Time to create this page: 12.7 ms