getcwd.3

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)getcwd.3	8.1	9/11/90
.TH getcwd 3 
.SH Name
getcwd \- get pathname of working directory
.SH Syntax
.nf
.B char \(\fI**getcwd (buf, size\fP)
.B char \(\fI**buf\fP;
.B int \fIsize\fP;
.fi
.SH Description
.NXR "getcwd subroutine (standard C)"
.NXR "working directory" "getting pathname"
.NXA "directory" "working directory"
The
.PN getcwd
subroutine returns a pointer to the current directory pathname.
The value of
.I size
must be at least two greater than the length of the
pathname to be returned.
.PP
If
.I buf
is a NULL pointer,
.PN getcwd
will obtain
.I size
bytes of space using 
.PN malloc (3) .
In this case, the pointer returned by
.PN getcwd
may be used as the argument in a subsequent call to
.I free.
.PP
The function is implemented by using 
.PN popen (3)
to pipe the output of the 
.PN pwd (1)
command into the specified string space.
.SH Examples
.EX
char \(**cwd, \(**getcwd();
\&.
\&.
\&.
if ((cwd = getcwd((char \(**)NULL, 64)) == NULL) {

     perror("pwd");
     exit(1);
}
printf("%s\en", cwd);
.EE
.SH Return Values
Returns NULL with
.I errno
set if
.I size
is not large enough, or if an error occurs
in a lower-level function.
.SH Diagnostics
.TP 15
[EINVAL]
The size argument is zero or negative.
.TP
[ERANGE]
The size argument is greater than zero, but is smaller
than the length of the pathname+1;
.TP
[EACCES]
Read or search permission is denied for a component of the
pathname.
.TP
[ENOMEM]
Insufficient storage space is available.
.SH See Also
pwd(1), malloc(3), popen(3)