fpathconf(2) System Calls fpathconf(2)
NAME
fpathconf, pathconf - get configurable pathname variables
SYNOPSIS
#include <unistd.h>
long fpathconf(int fildes, int name);
long pathconf(const char *path, int name);
DESCRIPTION
The fpathconf() and pathconf() functions determine the current value of a configurable limit or option ( variable ) 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 variables in the following table come from
<limits.h> or <unistd.h> and the symbolic constants, defined in <unistd.h>, are the corresponding values used for name:
+---------------------------+------------------------+--------------+
| Variable | Value of name | Notes |
+---------------------------+------------------------+--------------+
|{ACL_ENABLED} | _PC_ACL_ENABLED | 10 |
+---------------------------+------------------------+--------------+
|{FILESIZEBITS} | _PC_FILESIZEBITS | 3,4 |
+---------------------------+------------------------+--------------+
|{LINK_MAX} | _PC_LINK_MAX | 1 |
+---------------------------+------------------------+--------------+
|{MAX_CANON} | _PC_MAX_CANON | 2 |
+---------------------------+------------------------+--------------+
|{MAX_INPUT} | _PC_MAX_INPUT | 2 |
+---------------------------+------------------------+--------------+
|{NAME_MAX} | _PC_NAME_MAX | 3, 4 |
+---------------------------+------------------------+--------------+
|{PATH_MAX} | _PC_PATH_MAX | 4,5 |
+---------------------------+------------------------+--------------+
|{PIPE_BUF} | _PC_PIPE_BUF | 6 |
+---------------------------+------------------------+--------------+
|{POSIX_ALLOC_SIZE_MIN} | _PC_ALLOC_SIZE_MIN | |
+---------------------------+------------------------+--------------+
|{POSIX_REC_INCR_XFER_SIZE} | _PC_REC_INCR_XFER_SIZE | |
+---------------------------+------------------------+--------------+
|{POSIX_REC_MAX_XFER_SIZE} | _PC_REC_MAX_XFER_SIZE | |
+---------------------------+------------------------+--------------+
|{POSIX_REC_MIN_XFER_SIZE} | _PC_REC_MIN_XFER_SIZE | |
+---------------------------+------------------------+--------------+
|{POSIX_REC_XFER_ALIGN} | _PC_REC_XFER_ALIGN | |
+---------------------------+------------------------+--------------+
|{SYMLINK_MAX} | _PC_SYMLINK_MAX | 4, 9 |
+---------------------------+------------------------+--------------+
|{XATTR_ENABLED} | _PC_XATTR_ENABLED | 1 |
+---------------------------+------------------------+--------------+
|{XATTR_EXISTS} | _PC_XATTR_EXISTS | 1 |
+---------------------------+------------------------+--------------+
|_POSIX_CHOWN_RESTRICTED | _PC_CHOWN_RESTRICTED | 7 |
+---------------------------+------------------------+--------------+
|_POSIX_NO_TRUNC | _PC_NO_TRUNC | 3, 4 |
+---------------------------+------------------------+--------------+
|_POSIX_VDISABLE | _PC_VDISABLE | 2 |
+---------------------------+------------------------+--------------+
|_POSIX_ASYNC_IO | _PC_ASYNC_IO | 8 |
+---------------------------+------------------------+--------------+
|_POSIX_PRIO_IO | _PC_PRIO_IO | 8 |
+---------------------------+------------------------+--------------+
|_POSIX_SYNC_IO | _PC_SYNC_IO | 8 |
+---------------------------+------------------------+--------------+
Notes:
1. If path or fildes refers to a directory, the value returned applies to the directory itself.
2. If path or fildes does not refer to a terminal file, it is unspecified whether an implementation supports an association of the vari-
able name with the specified file.
3. If path or fildes refers to a directory, the value returned applies to filenames within the directory.
4. If path or fildes does not refer to a directory, it is unspecified whether an implementation supports an association of the variable
name with the specified file.
5. If path or fildes refers to a directory, the value returned is the maximum length of a relative pathname when the specified directory
is the working directory.
6. If path refers to a FIFO, or fildes refers to a pipe or FIFO, the value returned applies to the referenced object. If path or fildes
refers to a directory, the value returned applies to any FIFO that exists or can be created within the directory. If path or fildes
refers to any other type of file, it is unspecified whether an implementation supports an association of the variable name with the
specified file.
7. If path or fildes refers to a directory, the value returned applies to any files, other than directories, that exist or can be created
within the directory.
8. If path or fildes refers to a directory, it is unspecified whether an implementation supports an association of the variable name with
the specified file.
9. If path or fildes refers to a directory, the value returned is the maximum length of the string that a symbolic link in that directory
can contain.
10. If path or fildes refers to a file or directory in a file system that supports ACLs, the value returned is the bitwise inclusive OR of
the following flags associated with ACL types supported by the file system; otherwise 0 is returned.
_ACL_ACE_ENABLED The file system supports ACE ACLs.
_ACL_ACLENT_ENABLED The file system supports UFS aclent ACLs.
RETURN VALUES
If name is an invalid value, both pathconf() and fpathconf() return -1 and errno is set to indicate the error.
If the variable corresponding to name has no limit for the path or file descriptor, both pathconf() and fpathconf() return -1 without
changing errno. If pathconf() needs to use path to determine the value of name and pathconf() does not support the association of name with
the file specified by path, or if the process did not have appropriate privileges to query the file specified by path, or path does not
exist, pathconf() returns -1 and errno is set to indicate the error.
If fpathconf() needs to use fildes to determine the value of name and fpathconf() does not support the association of name with the file
specified by fildes, or if fildes is an invalid file descriptor, fpathconf() returns -1 and errno is set to indicate the error.
Otherwise pathconf() or fpathconf() returns the current variable value for the file or directory without changing errno. The value returned
will not be more restrictive than the corresponding value available to the application when it was compiled with <limits.h> or <unistd.h>.
ERRORS
The pathconf() function will fail if:
EINVAL The value of name is not valid.
ELOOP A loop exists in symbolic links encountered during resolution of the path argument.
The fpathconf() function will fail if:
EINVAL The value of name is not valid.
The pathconf() function may fail if:
EACCES Search permission is denied for a component of the path prefix.
EINVAL An association of the variable name with the specified file is not supported.
ENAMETOOLONG The length of the path argument exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}.
ENAMETOOLONG As a result of encountering a symbolic link in resolution of the path argument, the length of the substituted pathname
string exceeded {PATH_MAX}.
ENOENT A component of path does not name an existing file or path is an empty string.
ENOTDIR A component of the path prefix is not a directory.
The fpathconf() function may fail if:
EBADF The fildes argument is not a valid file descriptor.
EINVAL An association of the variable name with the specified file is not supported.
USAGE
The {SYMLINK_MAX} variable applies only to the fpathconf() function.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |Async-Signal-Safe |
+-----------------------------+-----------------------------+
SEE ALSO
confstr(3C), limits.h(3HEAD), sysconf(3C), attributes(5), standards(5)
SunOS 5.10 10 Sep 2004 fpathconf(2)