Name

pathconf, fpathconf − get configurable pathname variables (POSIX)

Syntax

#include <unistd.h>

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

long fpathconf(fildes, name)
int fildes, name;

Description

The pathconf() and fpathconf() functions provide a method for the application to determine the current value of a configurable limit or option that is associated with a file or directory.

For pathconf(,), the path argument points to the pathname of a file or directory. For fpathconf(,), the fildes argument is an open file descriptor. 

The name argument represents the variable to be queried relative to that file or directory. The following table lists the variables which may be queried and the corresponding value for the name argument. The values for the name argument are defined in the <unistd.h> header file. 

Variable                    name Value
 LINK_MAX                    _PC_LINK_MAX
MAX_CANON                   _PC_MAX_CANON
MAX_INPUT                   _PC_MAX_INPUT
NAME_MAX                    _PC_NAME_MAX
PATH_MAX                    _PC_PATH_MAX
PIPE_BUF                    _PC_PIPE_BUF
_POSIX_CHOWN_RESTRICTED     _PC_CHOWN_RESTRICTED
_POSIX_NO_TRUNC             _PC_NO_TRUNC
_POSIX_VDISABLE             _PC_VDISABLE

Return Values

Upon successful completion, the pathconf() and fpathconf() functions return the current variable value for the file or directory.

If name is an invalid value, pathconf() and fpathconf() return −1 and errno is set to indicate the reason. If the variable corresponding to name is not defined on the system, pathconf() and fpathconf() return −1 without changing the value of errno. 

Diagnostics

The pathconf() and fpathconf() functions fail if the following occurs:

[EINVAL] The value of the name argument is invalid. 

See Also

<unistd.h>