辅导:C++函数fpathconf()函数
来源:优易学  2011-10-28 14:00:43   【优易学:中国教育考试门户网】   资料下载   IT书店
  FPATHCONF
  Section: Linux Programmer's Manual (3 )
  Updated: 19930404
  NAME
  fpathconf, pathconf get configuration values for files
  SYNOPSIS
  #include <unistd.h>
  long fpathconf(int filedes, int name);
  long pathconf(char *path, int name);
  DESCRIPTION
  fpathconf() gets a value for the configuration option name for the open file descriptor filedes.
  pathconf() gets a value for configuration option name for the file name 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 filedes 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 filedes 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 filedes 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 filedes. 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 filedes is the current working directory. The corresponding macro is _POSIX_PATH_MAX.
  _PC_PIPE_BUF
  returns the size of the pipe buffer, where filedes 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 filedes or path refer to a directory, then this applies to all files in that directory. The corresponding macro is _POSIX_CHOWN_RESTRICTED.//http://examda.com
  _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 filedes 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.
  CONFORMING TO
  POSIX.1
  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), sysconf(3)

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