NAME
getcwd, getwd
— get working directory
pathname
SYNOPSIS
#include
<unistd.h>
char *
getcwd(char
*buf, size_t
size);
char *
getwd(char
*buf);
DESCRIPTION
The
getcwd()
function copies the absolute pathname of the current working directory into
the memory referenced by buf and returns a pointer to
buf. The size argument is the
size, in bytes, of the array referenced by buf.
If buf is NULL,
space is allocated as necessary to store the pathname. This space may later
be free(3)'d.
The function
getwd() is a
compatibility routine which calls getcwd() with its
buf argument and a size of
PATH_MAX (as defined in the include file
<limits.h>). Obviously,
buf should be at least
PATH_MAX bytes in length.
These routines have traditionally been used by programs to save the name of a working directory for the purpose of returning to it. A much faster and less error-prone method of accomplishing this is to open the current directory (.) and use the fchdir(2) function to return.
RETURN VALUES
Upon successful completion, a pointer to the pathname is returned.
Otherwise a null pointer is returned and the global variable
errno is set to indicate the error. In addition,
getwd() copies the error message associated with
errno into the memory referenced by
buf.
ERRORS
The getwd() function will fail if:
- [
EACCES] - Read or search permission was denied for a component of the pathname.
- [
EINVAL] - The size argument is zero.
- [
ENOENT] - A component of the pathname no longer exists.
- [
ENOMEM] - Insufficient memory is available.
- [
ERANGE] - The size argument is greater than zero but smaller than the length of the pathname plus 1.
SEE ALSO
STANDARDS
The getcwd() function conforms to
IEEE Std 1003.1-2001 (“POSIX.1”). The
ability to specify a null pointer and have getcwd()
allocate memory as necessary is an extension.
HISTORY
The getwd() function first appeared in
4.0BSD, and getcwd() in
4.3BSD-Net/2.
In OpenBSD 4.0,
getcwd() was reimplemented on top of the
__getcwd() system call. Its calling convention
differs from the standard function by requiring buf to
not be NULL and by returning an integer, zero on
success, and -1 with corresponding errno on failure. This is visible in the
output of kdump(1).
BUGS
The getwd() function does not do
sufficient error checking and is not able to return very long, but valid,
paths. It is provided for compatibility.