.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved .TH "GETCWD" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" .\" getcwd .SH NAME getcwd \- get the pathname of the current working directory .SH SYNOPSIS .LP \fB#include .br .sp char *getcwd(char *\fP\fIbuf\fP\fB, size_t\fP \fIsize\fP\fB); .br \fP .SH DESCRIPTION .LP The \fIgetcwd\fP() function shall place an absolute pathname of the current working directory in the array pointed to by \fIbuf\fP, and return \fIbuf\fP. The pathname copied to the array shall contain no components that are symbolic links. The \fIsize\fP argument is the size in bytes of the character array pointed to by the \fIbuf\fP argument. If \fIbuf\fP is a null pointer, the behavior of \fIgetcwd\fP() is unspecified. .SH RETURN VALUE .LP Upon successful completion, \fIgetcwd\fP() shall return the \fIbuf\fP argument. Otherwise, \fIgetcwd\fP() shall return a null pointer and set \fIerrno\fP to indicate the error. The contents of the array pointed to by \fIbuf\fP are then undefined. .SH ERRORS .LP The \fIgetcwd\fP() function shall fail if: .TP 7 .B EINVAL The \fIsize\fP argument is 0. .TP 7 .B ERANGE The \fIsize\fP argument is greater than 0, but is smaller than the length of the pathname +1. .sp .LP The \fIgetcwd\fP() function may fail if: .TP 7 .B EACCES Read or search permission was denied for a component of the pathname. .TP 7 .B ENOMEM Insufficient storage space is available. .sp .LP \fIThe following sections are informative.\fP .SH EXAMPLES .SS Determining the Absolute Pathname of the Current Working Directory .LP The following example returns a pointer to an array that holds the absolute pathname of the current working directory. The pointer is returned in the \fIptr\fP variable, which points to the \fIbuf\fP array where the pathname is stored. .sp .RS .nf \fB#include #include \&... long size; char *buf; char *ptr; .sp size = pathconf(".", _PC_PATH_MAX); .sp if ((buf = (char *)malloc((size_t)size)) != NULL) ptr = getcwd(buf, (size_t)size); \&... \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 \fIbuf\fP with \fIsize\fP {{PATH_MAX}+1}. .LP Having \fIgetcwd\fP() take no arguments and instead use the \fImalloc\fP() function to produce space for the returned argument was considered. The advantage is that \fIgetcwd\fP() knows how big the working directory pathname is and can allocate an appropriate amount of space. But the programmer would have to use the \fIfree\fP() function to free the resulting object, or each use of \fIgetcwd\fP() would further reduce the available memory. Also, \fImalloc\fP() and \fIfree\fP() are used nowhere else in this volume of IEEE\ Std\ 1003.1-2001. Finally, \fIgetcwd\fP() is taken from the SVID where it has the two arguments used in this volume of IEEE\ Std\ 1003.1-2001. .LP The older function \fIgetwd\fP() was rejected for use in this context because it had only a buffer argument and no \fIsize\fP argument, and thus had no way to prevent overwriting the buffer, except to depend on the programmer to provide a large enough buffer. .LP On some implementations, if \fIbuf\fP is a null pointer, \fIgetcwd\fP() may obtain \fIsize\fP bytes of memory using \fImalloc\fP(). In this case, the pointer returned by \fIgetcwd\fP() may be used as the argument in a subsequent call to \fIfree\fP(). Invoking \fIgetcwd\fP() with \fIbuf\fP as a null pointer is not recommended in conforming applications. .LP If a program is operating in a directory where some (grand)parent directory does not permit reading, \fIgetcwd\fP() may fail, as in most implementations it must read the directory to determine the name of the file. This can occur if search, but not read, permission is granted in an intermediate directory, or if the program is placed in that directory by some more privileged process (for example, login). Including the [EACCES] error condition makes the reporting of the error consistent and warns the application writer that \fIgetcwd\fP() can fail for reasons beyond the control of the application writer or user. Some implementations can avoid this occurrence (for example, by implementing \fIgetcwd\fP() using \fIpwd\fP, where \fIpwd\fP is a set-user-root process), thus the error was made optional. Since this volume of IEEE\ Std\ 1003.1-2001 permits the addition of other errors, this would be a common addition and yet one that applications could not be expected to deal with without this addition. .SH FUTURE DIRECTIONS .LP None. .SH SEE ALSO .LP \fImalloc\fP() , the Base Definitions volume of IEEE\ Std\ 1003.1-2001, \fI\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 .