Open Source Software

fpathconf(3)



NAME

   fpathconf, pathconf - get configuration values for files

SYNOPSIS

   #include <unistd.h>

   long fpathconf(int fd, int name);
   long pathconf(const char *path, int name);

DESCRIPTION

   fpathconf() gets a value for the configuration option name for the open
   file descriptor fd.

   pathconf() gets a value for configuration option name for the  filename
   path.

   The  corresponding  macros defined in <unistd.h> are minimum values; if
   an application wants to take advantage of values which  may  change,  a
   call  to  fpathconf()  or  pathconf() can be made, which may yield more
   liberal results.

   Setting name equal to  one  of  the  following  constants  returns  the
   following configuration options:

   _PC_LINK_MAX
          returns  the maximum number of links to the file.  If fd or path
          refer to a directory,  then  the  value  applies  to  the  whole
          directory.  The corresponding macro is _POSIX_LINK_MAX.

   _PC_MAX_CANON
          returns  the  maximum length of a formatted input line, where fd
          or path must refer to a terminal.  The  corresponding  macro  is
          _POSIX_MAX_CANON.

   _PC_MAX_INPUT
          returns  the  maximum  length of an input line, where fd or path
          must  refer  to  a  terminal.   The   corresponding   macro   is
          _POSIX_MAX_INPUT.

   _PC_NAME_MAX
          returns  the  maximum length of a filename in the directory path
          or fd that the process is allowed to create.  The  corresponding
          macro is _POSIX_NAME_MAX.

   _PC_PATH_MAX
          returns  the  maximum length of a relative pathname when path or
          fd is the current working directory.  The corresponding macro is
          _POSIX_PATH_MAX.

   _PC_PIPE_BUF
          returns  the  size  of the pipe buffer, where fd must refer to a
          pipe or FIFO and path must refer to a FIFO.   The  corresponding
          macro is _POSIX_PIPE_BUF.

   _PC_CHOWN_RESTRICTED
          returns  nonzero  if  the  chown(2) call may not be used on this
          file.  If fd or path refer to a directory, then this applies  to
          all  files  in  that  directory.   The  corresponding  macro  is
          _POSIX_CHOWN_RESTRICTED.

   _PC_NO_TRUNC
          returns   nonzero   if   accessing   filenames    longer    than
          _POSIX_NAME_MAX  generates an error.  The corresponding macro is
          _POSIX_NO_TRUNC.

   _PC_VDISABLE
          returns nonzero if special character processing can be disabled,
          where fd or path must refer to a terminal.

RETURN VALUE

   The  limit  is  returned, if one exists.  If the system does not have a
   limit for  the  requested  resource,  -1  is  returned,  and  errno  is
   unchanged.   If  there is an error, -1 is returned, and errno is set to
   reflect the nature of the error.

ATTRIBUTES

   For  an  explanation  of  the  terms  used   in   this   section,   see
   attributes(7).

   
   Interface                Attribute      Value   
   
   fpathconf(), pathconf()  Thread safety  MT-Safe

CONFORMING TO

   POSIX.1-2001, POSIX.1-2008.

NOTES

   Files  with  name lengths longer than the value returned for name equal
   to _PC_NAME_MAX may exist in the given directory.

   Some returned values may be huge; they are not suitable for  allocating
   memory.

SEE ALSO

   getconf(1), open(2), statfs(2), confstr(3), sysconf(3)

COLOPHON

   This  page  is  part of release 4.09 of the Linux man-pages project.  A
   description of the project, information about reporting bugs,  and  the
   latest     version     of     this    page,    can    be    found    at
   https://www.kernel.org/doc/man-pages/.



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