fpathconf()--Get Configurable Path Name Variables by Descriptor

 #include <unistd.h>

 long fpathconf(int file_descriptor, int name);  

The fpathconf() function determines the value of a configuration variable (name) associated with a particular file descriptor (file_descriptor). fpathconf() works exactly like pathconf(), except that it takes a file descriptor as an argument rather than taking a path name.

If file_descriptor is a descriptor for a socket, fpathconf() returns an error of [EINVAL].

Parameters

file_descriptor

(Input) A file descriptor of the file for which the value of the configurable variable is requested.

name

(Input) The name of the configuration variable value requested.

The value of name can be any one of a set of symbols defined in the <unistd.h> include file. For more information, see pathconf()--Get Configurable Path Name Variables

Authorities

No authorization is required.

Return Value

value

fpathconf() was successful. The value of the variable requested in name is returned.

-1

One of the following has occurred:

• A particular variable has no limit (for example, _PC_PATH_MAX). The errno global variable is not changed.
  
• fpathconf() was not successful. The errno is set.

Error Conditions

If fpathconf() 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

Related Information

• The <unistd.h> file (see Header Files for UNIX-Type Functions)
  
• open()--Open File
  
• pathconf()--Get Configurable Path Name Variables
  
• QlgPathconf()--Get Configurable Path Name Variables

Example

See Code disclaimer information for information pertaining to code examples.

The following example uses fpathconf():

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>

main() {
  long result;
  char fn[]="temp.file";
  int  file_descriptor;

  if ((file_descriptor = creat(fn, S_IRUSR)) < 0)
    perror("creat() error");
  else {
    errno = 0;
    puts("examining NAME_MAX limit for current working directory's");
    puts("filesystem:");
    if ((result = fpathconf(file_descriptor, _PC_NAME_MAX)) == -1)
      if (errno == 0)
        puts("There is no limit to NAME_MAX.");
      else perror("fpathconf() error");
    else
      printf("NAME_MAX is %ld\n", result);
    close(file_descriptor);
    unlink(fn);
  }
}

Output:

examining NAME_MAX limit for current working directory's
filesystem:
NAME_MAX is 255