FPATHCONF

fpathconf, pathconf ? get configuration values for files

#include <unistd.h>

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

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.

_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.

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.

POSIX.1

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.

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