getwd(3) [osx man page]

GETCWD(3)						   BSD Library Functions Manual 						 GETCWD(3)

NAME

     getcwd, getwd -- get working directory pathname

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <unistd.h>

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

     char *
     getwd(char *buf);

DESCRIPTION

     The getcwd() 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 getwd() is a compatibility routine which calls getcwd() with its buf argument and a size of MAXPATHLEN (as defined in the
     include file <sys/param.h>).  Obviously, buf should be at least MAXPATHLEN 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.

RETURN VALUES

     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.

ERRORS

     The getcwd() function will fail if:

     [EACCES]		Read or search permission was denied for a component of the pathname.

     [EINVAL]		The size argument is zero.

     [ENOENT]		A component of the pathname no longer exists.

     [ENOMEM]		Insufficient memory is available.

     [ERANGE]		The size argument is greater than zero but smaller than the length of the pathname plus 1.

SEE ALSO

     chdir(2), fchdir(2), malloc(3), strerror(3)

STANDARDS

     The getcwd() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1'').  The ability to specify a NULL pointer and have getcwd() allocate memory
     as necessary is an extension.

HISTORY

     The getwd() function appeared in 4.0BSD.

BUGS

     The getwd() function does not do sufficient error checking and is not able to return very long, but valid, paths.	It is provided for compat-
     ibility.

BSD
								 November 24, 1997							       BSD

GETCWD(3)						     Linux Programmer's Manual							 GETCWD(3)

NAME

       getcwd, get_current_dir_name, getwd - Get current working directory

SYNOPSIS

       #include <unistd.h>

       char *getcwd(char *buf, size_t size);
       char *get_current_dir_name(void);
       char *getwd(char *buf);

DESCRIPTION

       The getcwd() function copies an absolute pathname of the current working directory to the array pointed to by buf, which is of length size.

       If the current absolute path name would require a buffer longer than size elements, NULL is returned, and errno is set to ERANGE; an appli-
       cation should check for this error, and allocate a larger buffer if necessary.

       If buf is NULL, the behaviour of getcwd() is undefined.

       As an extension to the POSIX.1 standard, Linux (libc4, libc5, glibc) getcwd() allocates the buffer dynamically using  malloc()  if  buf	is
       NULL  on  call.	In this case, the allocated buffer has the length size unless size is zero, when buf is allocated as big as necessary.	It
       is possible (and, indeed, advisable) to free() the buffers if they have been obtained this way.

       get_current_dir_name, which is only prototyped if _GNU_SOURCE is defined, will malloc(3) an array big enough to hold the current  directory
       name.  If the environment variable PWD is set, and its value is correct, then that value will be returned.

       getwd, which is only prototyped if _BSD_SOURCE or _XOPEN_SOURCE_EXTENDED is defined, will not malloc(3) any memory. The buf argument should
       be a pointer to an array at least PATH_MAX bytes long.  getwd does only return the first PATH_MAX bytes of the actual pathname.	Note  that
       PATH_MAX  need not be a compile-time constant; it may depend on the filesystem and may even be unlimited. For portability and security rea-
       sons, use of getwd is deprecated.

RETURN VALUE

       NULL on failure with errno set accordingly, and buf on success. The contents of the array pointed to by buf is undefined on error.

ERRORS

       EACCES Permission to read or search a component of the file name was denied.

       EFAULT buf points to a bad address.

       EINVAL The size argument is zero and buf is not a null pointer.

       ENOENT The current working directory has been unlinked.

       ERANGE The size argument is less than the length of the working directory name.	You need to allocate a bigger array and try again.

NOTES

       Under Linux, the function getcwd() is a system call (since 2.1.92).  On older systems it would query /proc/self/cwd.  If both  system  call
       and proc file system are missing, a generic implementation is called. Only in that case can these calls fail under Linux with EACCES.

       These  functions are often used to save the location of the current working directory for the purpose of returning to it later. Opening the
       current directory (".") and calling fchdir(2) to return is usually a faster and more  reliable  alternative  when  sufficiently	many  file
       descriptors are available, especially on platforms other than Linux.

CONFORMING TO

       POSIX.1

SEE ALSO

       chdir(2), fchdir(2), open(2), unlink(2), free(3), malloc(3)

GNU
								    2002-04-22								 GETCWD(3)