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