PATHCONF(2) BSD System Calls Manual PATHCONF(2)NAME
pathconf, fpathconf — get configurable pathname variables
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
long
pathconf(const char *path, int name);
long
fpathconf(int fd, int name);
DESCRIPTION
The pathconf() and fpathconf() functions provide a method for applica‐
tions to determine the current value of a configurable system limit or
option variable associated with a pathname or file descriptor.
For pathconf(), the path argument is the name of a file or directory.
For fpathconf(), the fd argument is an open file descriptor. The name
argument specifies the system variable to be queried. Symbolic constants
for each name value are found in the include file <unistd.h>.
The available values are as follows:
_PC_LINK_MAX
The maximum file link count.
_PC_MAX_CANON
The maximum number of bytes in terminal canonical input line.
_PC_MAX_INPUT
The minimum maximum number of bytes for which space is available
in a terminal input queue.
_PC_NAME_MAX
The maximum number of bytes in a file name.
_PC_PATH_MAX
The maximum number of bytes in a pathname.
_PC_PIPE_BUF
The maximum number of bytes which will be written atomically to a
pipe.
_PC_CHOWN_RESTRICTED
Return 1 if appropriate privileges are required for the chown(2)
system call, otherwise 0.
_PC_NO_TRUNC
Return 1 if file names longer than KERN_NAME_MAX are truncated.
_PC_VDISABLE
Returns the terminal character disabling value.
RETURN VALUES
If the call to pathconf() or fpathconf() is not successful, -1 is
returned and errno is set appropriately. Otherwise, if the variable is
associated with functionality that does not have a limit in the system,
-1 is returned and errno is not modified. Otherwise, the current vari‐
able value is returned.
ERRORS
If any of the following conditions occur, the pathconf() and fpathconf()
functions shall return -1 and set errno to the corresponding value.
[EINVAL] The value of the name argument is invalid.
[EINVAL] The implementation does not support an association of
the variable name with the associated file.
Pathconf() will fail if:
[ENOTDIR] A component of the path prefix is not a directory.
[ENAMETOOLONG] A component of a pathname exceeded 255 characters, or
an entire path name exceeded 1023 characters.
[ENOENT] The named file does not exist.
[EACCES] Search permission is denied for a component of the
path prefix.
[ELOOP] Too many symbolic links were encountered in translat‐
ing the pathname.
[EIO] An I/O error occurred while reading from or writing to
the file system.
Fpathconf() will fail if:
[EBADF] fd is not a valid open file descriptor.
[EIO] An I/O error occurred while reading from or writing to
the file system.
SEE ALSOsysctl(3)HISTORY
The pathconf() and fpathconf() functions first appeared in 4.4BSD.
BSD June 4, 1993 BSD
