fpathconf (BPX1FPC, BPX4FPC) — Determine configurable path name variables using a descriptor

Function

The fpathconf callable service determines the current values of a configurable limit or option (variable) that is associated with a file or directory.

Requirements

Parameters

File_descriptor

Supplied parameter

Type:

Integer

Length:

Fullword

The name of a fullword that contains the file descriptor of the file.

Name

Supplied parameter

Type:

Integer

Length:

Fullword

The name of a fullword that contains a value that indicates which configurable limit or option (variable) is to be returned in the Return_value. Use the BPXYPFC macro (see BPXYPCF — Command values for pathconf and pathconf) to specify the path name variable you want returned. The following table shows the variables that can be returned:

Variable returned	Description
PC_CHOWN_RESTRICTED	The change ownership ( chown (BPX1CHO, BPX4CHO) — Change the owner or group of a file or directory) function is restricted to processes with appropriate privileges (see Authorization). The group ID (GID) of a file can be changed only to the effective group ID of the process, or to one of its supplementary group IDs.
PC_LINK_MAX	The maximum value of a file's link count.
PC_MAX_CANON	The maximum number of bytes in a terminal canonical input line.
PC_MAX_INPUT	The minimum number of bytes for which space will be available in a terminal input queue. This is the maximum number of bytes a portable application may require to be typed as input before it reads them.
PC_NAME_MAX	The maximum number of bytes in a file name (not a string length; the count excludes a terminating null).
PC_NO_TRUNC	Path name components longer than 255 bytes generate an error.
PATH_MAX	The maximum number of bytes in a path name (not a string length; the count excludes a terminating null).
PIPE_BUF	The maximum number of bytes that can be written atomically when writing to a pipe.
_POSIX_VDISABLE	Terminal special characters maintained by the system can be disabled using this character value. For information on querying and setting these special characters, see tcgetattr (BPX1TGA, BPX4TGA) — Get the attributes for a terminal or tcsetattr (BPX1TSA, BPX4TSA) — Set the attributes for a terminal.
PC_ACL	The security product supports access control lists.
PC_ACL_ENTRIES_MAX	The maximum number of entries that can be placed in an access control list for the specified file.

Return_value

Returned parameter

Type:

Integer

Length:

Fullword

The name of a fullword in which the fpathconf service returns the current value of the Pathname variable that corresponds to the Name specified, or -1 if the request is not successful.

If the named Pathname variable does not have a limit for the specified file, Return_value is set to -1 and the Return_code and Reason_code remain unchanged.

If PC_CHOWN_RESTRICTED is specified for Name, and PC_CHOWN_RESTRICTED is active, Return_value is set to 1.

If PC_CHOWN_RESTRICTED is specified for Name, and PC_CHOWN_RESTRICTED is not active, Return_value is set to 0.

If PC_NO_TRUNC is specified for Name, and PC_NO_TRUNC is active, Return_value is set to 1.

If PC_NO_TRUNC is specified for Name, and PC_NO_TRUNC is not active, Return_value is set to 0.

If PC_ACL is specified for Name, and PC_ACL is supported, Return_value is set to 1.

If PC_ACL is specified for Name, and PC_ACL is not supported, Return_value is set to 0.

Return_code

Returned parameter

Type:

Integer

Length:

Fullword

The name of a fullword in which the fpathconf service stores the return code. The fpathconf service returns Return_code only if Return_value is -1. For a complete list of possible return code values, see z/OS UNIX System Services Messages and Codes.

If the named Pathname variable does not have a limit for the specified file, Return_value is -1 and Return_code is unchanged. Otherwise, the fpathconf service can return one of the following values in the Return_code parameter:

Return_code	Explanation
EBADF	The File_descriptor argument is not a valid file descriptor.
EINVAL	Refer to the usage notes for situations in which this is returned.

Reason_code

Returned parameter

Type:

Integer

Length:

Fullword

The name of a fullword where the fpathconf service stores the reason code. The fpathconf service returns Reason_code only if Return_value is -1. Reason_code further qualifies the Return_code value. For the reason codes, see z/OS UNIX System Services Messages and Codes.

Usage notes

1. If Name refers to MAX_CANON, MAX_INPUT, or _POSIX_VDISABLE, the following applies:
   • If File_descriptor does not refer to a terminal file, the function returns -1 in Return_value and sets the Return_code to EINVAL.
2. If Name refers to NAME_MAX, PATH_MAX, or _POSIX_NO_TRUNC, the following applies:
   • If File_descriptor does not refer to a directory, the function still returns the requested information using the parent directory of the specified file.
3. If Name refers to PC_PIPE_BUF, the following applies:
   • If File_descriptor refers to a pipe or a FIFO, the value returned applies to the referred-to object itself. If File_descriptor refers to a directory, the value returned applies to any FIFOs that exist or that can be created within the directory. If File_descriptor refers to any other type of file, the function returns -1 in Return_value and sets the Return_code to EINVAL.
4. If Name refers to PC_LINK_MAX, the following applies:
   • If File_descriptor refers to a directory, the value returned applies to the directory.

Related services

• pathconf (BPX1PCF, BPX4PCF) — Determine configurable path name variables using a path name

Characteristics and restrictions

There are no restrictions on the use of the fpathconf service.