fchdir()--Change Current Directory by Descriptor

 #include <unistd.h>

 int fchdir(int fildes);  

The fchdir() function makes the directory named by fildes the new current directory. If the fchdir() function fails, the current directory is unchanged.

Parameters

fildes

(Input) The file descriptor of the directory.

Authorities

Note: Adopted authority is not used.

Authorization Required for fchdir()

Object Referred to	Authority Required	errno
The directory named by fildes.	*X	EACCES

Return Value

0

fchdir() was successful.

-1

fchdir() was not successful. The errno global variable is set to indicate the error.

Error Conditions

If fchdir() is not successful, errno usually indicates one of the following errors. Under some conditions, errno could indicate an error other than those listed here.

If interaction with a file server is required to access the object, errno could indicate one of the following errors:

Error Messages

The following messages may be sent from this function:

Usage Notes

1. This function will fail with error code [ENOTSAFE] when all the following conditions are true:
   
   
   • Where multiple threads exist in the job.
     
   • The object on which this function is operating resides in a file system that is not threadsafe. Only the following file systems are threadsafe for this function:
     
     
     • "Root" (/)
     • QOpenSys
     • User-defined
     • QNTC
     • QSYS.LIB
     • Independent ASP QSYS.LIB
     • QOPT
     • Network File System
     • QFileSvr.400

   The fchdir() API operates on two objects: the previous current working directory and the new one. If either of these objects is managed by a file system that is not threadsafe, fchdir() fails with the ENOTSAFE error code.

2. Network File System Differences

   If the local storage of attributes and names is not suppressed (option noac when the file system is mounted), then one can potentially use the fchdir() API to change to a directory which has been removed. This depends on how often and when the local storage of attributes and names is refreshed.

Related Information

• The <unistd.h> file (see Header Files for UNIX-Type Functions)
• The <limits.h> file (see Header Files for UNIX-Type Functions)
• chdir()--Change Current Directory
• getcwd()--Get Current Directory
• QlgChdir()--Change Current Directory
• QlgGetcwd()--Get Current Directory

Example

See Code disclaimer information for information pertaining to code examples.

The following example uses fchdir():

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

main() {
  char dir[]="tempfile";
  int  file_descriptor;
  int oflag1 = O_RDONLY | O_CCSID;
  mode_t mode = S_IRUSR | S_IWUSR | S_IXUSR;
  unsigned int open_ccsid = 37;

  if ((file_descriptor = open(dir,oflag1,mode,open_ccsid)) < 0)
    perror("open() error");
  else { 
    if (fchdir(file_descriptor) != 0)
      perror("fchdir() to tempfile failed");
    close(file_descriptor);
  } 
}

Output:

fchdir() to tempfile failed: Not a directory.