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NAME

       getcwd, getwd, get_current_dir_name - Get current working directory

SYNOPSIS

       #include <unistd.h>

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

       char *getwd(char *buf);

       char *get_current_dir_name(void);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getcwd(): _BSD_SOURCE || _XOPEN_SOURCE >= 500
       get_current_dir_name(): _GNU_SOURCE

DESCRIPTION

       These  functions return a null-terminated string containing an absolute
       pathname that is the current working directory of the calling  process.
       The  pathname  is  returned as the function result and via the argument
       buf, if present.

       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  length  of  the  absolute  pathname  of  the  current  working
       directory,  including  the  terminating  null byte, exceeds size bytes,
       NULL is returned, and errno is set to  ERANGE;  an  application  should
       check for this error, and allocate a larger buffer if necessary.

       As  an  extension  to  the  POSIX.1-2001 standard, Linux (libc4, libc5,
       glibc) getcwd() allocates the buffer dynamically using malloc(3) if buf
       is NULL.  In this case, the allocated buffer has the length size unless
       size is zero, when buf is allocated as big as  necessary.   The  caller
       should free(3) the returned buffer.

       get_current_dir_name()  will  malloc(3) an array big enough to hold the
       absolute pathname of the current working directory.  If the environment
       variable  PWD is set, and its value is correct, then that value will be
       returned.  The caller should free(3) the returned buffer.

       getwd() does not malloc(3) any memory.  The buf argument  should  be  a
       pointer to an array at least PATH_MAX bytes long.  If the length of the
       absolute pathname of  the  current  working  directory,  including  the
       terminating  null  byte,  exceeds PATH_MAX bytes, NULL is returned, and
       errno is set to ENAMETOOLONG.  (Note that on some systems, PATH_MAX may
       not  be  a  compile-time constant; furthermore, its value may depend on
       the file  system,  see  pathconf(3).)   For  portability  and  security
       reasons, use of getwd() is deprecated.

RETURN VALUE

       On success, these functions return a pointer to a string containing the
       pathname of the current working directory.  In the  case  getcwd()  and
       getwd() this is the same value as buf.

       On  failure,  these functions return NULL, and errno is set to indicate
       the error.  The contents of the array pointed to by buf  are  undefined
       on error.

ERRORS

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

       EFAULT buf points to a bad address.

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

       EINVAL getwd(): buf is NULL.

       ENAMETOOLONG
              getwd(): The  size  of  the  null-terminated  absolute  pathname
              string exceeds PATH_MAX bytes.

       ENOENT The current working directory has been unlinked.

       ERANGE The  size  argument  is  less  than  the  length of the absolute
              pathname of the working  directory,  including  the  terminating
              null byte.  You need to allocate a bigger array and try again.

CONFORMING TO

       getcwd()  conforms  to  POSIX.1-2001.   Note  however that POSIX.1-2001
       leaves the behavior of getcwd() unspecified if buf is NULL.

       getwd() is present in POSIX.1-2001, but  marked  LEGACY.   POSIX.1-2008
       removes   the   specification   of   getwd().   Use  getcwd()  instead.
       POSIX.1-2001 does not define any errors for getwd().

       get_current_dir_name() is a GNU extension.

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.

SEE ALSO

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

COLOPHON

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