GETCWD(3C) Standard C Library Functions GETCWD(3C)

NAME

getcwd - get pathname of current working directory

SYNOPSIS

#include <unistd.h>

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

DESCRIPTION

The getcwd() function returns a pointer to a buffer containing the
absolute pathname of the current working directory. The returned
pathname contains no components that are symbolic links.

When buf is not NULL, the absolute pathname will be written into buf
and size represents the length in bytes of buf. If the length of the
pathname and nul terminator exceeds size, nothing will be written and
getcwd() will return NULL. Otherwise, getcwd() returns buf.

When buf is NULL then getcwd() will allocate memory in which to store
the pathname of the current working directory. If size is non-zero,
then size bytes will be allocated. If the length of the pathname and
nul terminator exceeds size, the memory will be freed and getcwd() will
return NULL. If size is zero, then getcwd() will attempt to allocate
enough space to hold the pathname. In both cases, it is the caller's
responsibility to free the returned buffer with the free(3C) function.

RETURN VALUES

Upon successful completion, the getcwd() function returns a pointer to
a buffer containing the pathname. Otherwise, NULL is returned and
errno is set to indicate the error.

EXAMPLES

Example 1 Determine the absolute pathname of the current working
directory.

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 ptr variable, which points to the buf array where the
pathname is stored.

#include <stdlib.h>
#include <unistd.h>
...
long size;
char *buf;
char *ptr;
size = pathconf(".", _PC_PATH_MAX);
if ((buf = (char *)malloc((size_t)size)) != NULL)
ptr = getcwd(buf, (size_t)size);
...

Example 2 Print the current working directory.

The following example prints the current working directory.

#include <stdio.h>
#include <unistd.h>

int
main(void)
{
char *cwd;

if ((cwd = getcwd(NULL, 0)) == NULL) {
perror("pwd");
exit(2);
}
(void)printf("%s\n", cwd);
free(cwd); /* free memory allocated by getcwd() */
return(0);
}

ERRORS

The getcwd() function will fail if:

EFAULT The buf argument points to an invalid address.

EINVAL The buf argument is not NULL and the size argument
is 0.

ERANGE The pathname (including its terminating nul
character) is too long to fit into the provided (or
allocated) buffer.

EACCESS A parent directory cannot be read to get its name.

ENOMEM Insufficient storage space is available.

USAGE

Applications should exercise care when using chdir(2) in conjunction
with getcwd(). The current working directory is global to all threads
within a process. If more than one thread calls chdir(2) to change the
working directory, a subsequent call to getcwd() could produce
unexpected results.

INTERFACE STABILITY

Committed

SEE ALSO

chdir(2), free(3C), attributes(7), standards(7)

illumos February 27, 2021 illumos