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GETCWD(3) Library Functions Manual GETCWD(3)

getcwd, getwdget working directory pathname

#include <unistd.h>

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

char *
getwd(char *buf);

The () 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 () 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.

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.

The getwd() function will fail if:

Read or search permission was denied for a component of the pathname.
The size argument is zero.
A component of the pathname no longer exists.
Insufficient memory is available.
The size argument is greater than zero but smaller than the length of the pathname plus 1.

pwd(1), chdir(2), malloc(3), strerror(3)

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.

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).

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.

July 5, 2019 OpenBSD-6.9