pathconf()

return the value of a configurable limit

Synopsis:

#include <unistd.h>
long pathconf( const char *path, int name );

Description:

The pathconf() function returns a value of a configurable limit indicated by name, which is associated with the filename given in path.

Configurable limits are defined in <unistd.h>, and contain at least the following values:

_PC_LINK_MAX

Maximum value of a files link count.

_PC_MAX_CANON

Maximum number of bytes in a terminals canonical input buffer (edit buffer).

_PC_MAX_INPUT

Maximum number of bytes in a terminals raw input buffer.

_PC_NAME_MAX

Maximum number of bytes in a file name (not including the terminating null).

_PC_PATH_MAX

Maximum number of bytes in a pathname (not including the terminating null).

_PC_PIPE_BUF

Maximum number of bytes that can be written atomically when writing to a pipe.

_PC_CHOWN_RESTRICTED

If defined (not -1), indicates that the use of the chown() function is restricted to a process with appropriate privileges, and to changing the group ID of a file to the effective group ID of the process or to one of its supplementary group IDs.

_PC_NO_TRUNC

If defined (not -1), indicates that the use of pathname components longer than the value given by _PC_NAME_MAX will generate an error.

_PC_VDISABLE

If defined (not -1), this is the character value which can be used to individually disable special control characters in the termios control structure.

Returns:

The requested configurable limit. If an error occurs, pathconf() returns -1, and errno is set.

Errors:

EINVAL

name is invalid, or the indicated limit is not supported.

EACCES

Search permission is denied for a component of path.

ENAMETOOLONG

path, or a component of path, is too long.

ENOENT

The file does not exist.

ENOTDIR

A component of the path prefix is not a directory.

Examples:

#include <stdio.h>
#include <unistd.h>

void main()
  {
    long value;

    value = pathconf( "/dev/con1", _PC_MAX_INPUT );
    printf( "Input buffer size is %ld bytes\n",
        value );
  }

Classification:

POSIX 1003.1

See also:

errno, fpathconf()