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) 来源：考试大