Updated: 11 December 1998

OpenVMS I/O User's Reference Manual

The read or write attributes subfunction is controlled by the attribute list specified by P5. The list consists of a variable number of two longword control blocks, terminated by a 0 longword, as shown in Figure 1-6. The maximum number of attribute control blocks in one list is 30. Table 1-6 describes the attribute control block fields.

Figure 1-6 Attribute Control Block Format

Table 1-6 Attribute Control Block Fields

Field	Meaning
ATR$W_SIZE	Specifies the number of bytes of the attribute to be transferred. Legal values are from 0 to the maximum size of the particular attribute (see Table 1-7).
ATR$W_TYPE	Identifies the individual attribute to be read or written.
ATR$L_ADDR	Contains the buffer address of the memory space to or from which the attribute is to be transferred. The attribute buffer must be writable.

Table 1-7 lists the valid attributes for ACP-QIO functions. The maximum size (in bytes) is determined by the required attribute configuration. For example, the Radix-50 file name (ATR$S_FILNAM) uses only 6 bytes, but it is always accompanied by the file type and file version, so a total of 10 bytes is required. Each attribute has two names: one for the code (for example, ATR$C_UCHAR) and one for the size (for example, ATR$S_UCHAR).

Table 1-7 ACP-QIO Attributes

Attribute Name6	Maximum Size (bytes)	Meaning
ATR$C_UCHAR 2 3	4	4-byte file characteristics. (The file characteristics bits are listed following this table.)
ATR$C_RECATTR 4	32	Record attribute area. Section 1.4 describes the record attribute area in detail.
ATR$C_FILNAM	10	6-byte Radix-50 file name plus ATR$C_FILTYP and ATR$C_FILVER.
ATR$C_FILTYP	4	2-byte Radix-50 file type plus ATR$C_FILVER.
ATR$C_FILVER	2	2-byte binary version number.
ATR$C_EXPDAT 2	7	Expiration date in ASCII. Format: DDMMMYY.
ATR$C_STATBLK	32	Statistics block. This attribute is read only. Section 1.5 describes the statistics block in detail.
ATR$C_HEADER	512	Complete file header. This attribute is read only.
ATR$C_BLOCKSIZE	2	Magnetic tape block size.
ATR$C_USERLABEL	80	User file label. This attribute is not supported for disk devices.
ATR$C_ASCDATES 2 3	35	Revision count (2 binary bytes), revision date, creation date, and expiration date, in ASCII. Format: DDMMMYY (revision date), HHMMSS (time), DDMMMYY (creation date), HHMMSS (time), DDMMMYY (expiration date). (The format contains no embedded spaces or commas.)
ATR$C_ALCONTROL	14	Compatibility mode allocation data.
ATR$C_ENDLBLAST	4	End of magnetic tape label processing; provides AST control block.
ATR$C_ASCNAME	86	Disk: file name, type, and version, in ASCII, including punctuation. Format: name.type;version. Magnetic tape: contains 17-character file identifier (ANSI a); no version number. Overrides all other file name and file type specifications if supplied on input operations. If specified on an access operation and you want only a value to be returned, specify (in ATR$W_SIZE) a buffer of greater than 17 bytes.
ATR$C_CREDATE 2	8	64-bit creation date and time.
ATR$C_REVDATE 2 4	8	64-bit revision date and time.
ATR$C_EXPDATE 2	8	64-bit expiration date and time.
ATR$C_BAKDATE 4 5 8 10	8	64-bit backup date and time.
ATR$C_UIC 2	4	4-byte file owner UIC.
ATR$C_FPRO 2 4	2	File protection.
ATR$C_RPRO 10	2	2-byte record protection.
ATR$C_ACLEVEL 2 4 5 10	1	File access level.
ATR$C_SEMASK 10	8	File security mask and limit.
ATR$C_UIC_RO	4	4-byte file owner UIC. This attribute is read only.
ATR$C_DIRSEQ 10	2	Directory update sequence count.
ATR$C_BACKLINK 10	6	File back link pointer.
ATR$C_JOURNAL 10	1	Journal control flags.
ATR$C_HDR1_ACC	1	ANSI magnetic tape header label accessibility character.
ATR$C_ADDACLENT 7 10 11	255	Adds an ACE to the beginning of the ACL when the ACE context value is 0; to the end of the ACL when the ACE context value is --1; or at a location pointed to by a prior ACL$C_FNDACETYP or ACL$C_FNDACLENT.
ATR$C_DELACLENT 7 10 11	255	Deletes an access control entry pointed to by the buffer address or, if the buffer address is 0, the ACE pointed to by a prior ACL$C_FNDACETYP or ACL$C_FNDACLENT.
ATR$C_MODACLENT 7 10 11	255	Replaces the ACE pointed to by a prior ACL$C_FNDACETYP or ACL$C_FNDACLENT with the ACE pointed to by its buffer address.
ATR$C_FNDACLENT 10 11	255	Locates an ACE pointed to by its buffer address.
ATR$C_FNDACETYP 10 11	255	Locates an ACE of the type pointed to by its buffer address.
ATR$C_DELETEACL 7 10 11	255	Deletes the entire ACL with the exception of protected ACEs.
ATR$C_READACL 10 11	512	Reads the entire ACL or as much as will fit in the supplied buffer. Only complete ACEs are transferred.
ATR$C_ACLLENGTH 10 11	4	Returns the size, in bytes, of the object's ACL.
ATR$C_READACE 10 11	255	Reads the ACE pointed to by ACL$C_FNDACETYP or ACL$C_FNDACLENT into the buffer.
ATR$C_RESERVED 9 10	380	Modifies the reserve area.
ATR$C_HIGHWATER 10	4	High-water mark (user read-only).
ATR$C_PRIVS_USED 10	4	Privileges used to gain access. This attribute can only be retrieved on the initial file access or create operation.
ATR$C_MATCHING_ACE 8 10	255	ACE used to gain access (if any). This attribute can only be retrieved on the initial file access or create operation.
ATR$C_ACCESS_MODE	1	Access mode for following attribute descriptors.
ATR$C_FILE_SPEC 10	512	Convert FID to file specification.
ATR$C_BUFFER_OFFSET 3	2	Offset length for ANSI magnetic tape header label buffer.
ATR$C_DELETE_ALL 7 10 11	255	Delete the entire ACL, including protected entries.
ATR$C_GRANT_ACE 10 11	255	Return an ACE that grants or denies access to the object.
ATR$C_NEXT_ACE 10 11	4	Advance to the next ACE in the ACL.

Table 1-8 lists the bits contained in the file characteristics longword, which is read with the ATR$C_UCHAR attribute.

Table 1-8 File Characteristics Bits

FCH$M_NOBACKUP	Do not back up file.
FCH$M_READCHECK	Verify all read operations.
FCH$M_WRITCHECK	Verify all write operations.
FCH$M_CONTIGB	Keep file as contiguous as possible.
FCH$M_LOCKED	File is deaccess-locked.
FCH$M_CONTIG	File is contiguous.
FCH$M_BADACL	File's ACL is corrupt.
FCH$M_SPOOL	File is an intermediate spool file.
FCH$M_DIRECTORY	File is a directory.
FCH$M_BADBLOCK	File contains bad blocks.
FCH$M_MARKDEL	File is marked for deletion.
FCH$M_ERASE	Erase file contents before deletion.
FCH$M_ASSOCIATED 1	File has an associated file.
FCH$M_EXISTENCE 1	Suppress existence of file.
FCH$M_NOMOVE	Disable movefile operations on this file.
FCH$M_NOSHELVABLE	File is not shelvable.
FCH$M_SHELVED	File is shelved.

Figure 1-7 shows the format of the record attributes area.

Figure 1-7 ACP-QIO Record Attributes Area

Table 1-9 lists the record attributes values and their meanings.

Table 1-9 ACP Record Attributes Values

Field Value	Meaning
FAT$B_RTYPE	Record type. Contains FAT$V_RTYPE and FAT$V_FILEORG.
FAT$V_RTYPE	Record type. The following bit values are defined: FAT$C_FIXED Fixed-length record FAT$C_VARIABLE Variable-length record FAT$C_VFC Variable-length record with fixed control FAT$C_UNDEFINED Undefined record format (stream binary) FAT$C_STREAM RMS stream format FAT$C_STREAMLF Stream terminated by LF FAT$C_STREAMCR Stream terminated by CR
FAT$V_FILEORG	File organization. The following bit values are defined: FAT$C_DIRECT Direct file organization 1 FAT$C_INDEXED Indexed file organization FAT$C_RELATIVE Relative file organization FAT$C_SEQUENTIAL Sequential file organization
FAT$B_RATTRIB	Record attributes. The following bit values are defined: FAT$M_FORTRANCC FORTRAN carriage control FAT$M_IMPLIEDCC Implied carriage control FAT$M_PRINTCC Print file carriage control FAT$M_NOSPAN No spanned records FAT$M_MSBRCW 4 Record count word (RCW) is MSB formatted
FAT$W_RSIZE	Record size in bytes.
FAT$L_HIBLK 2	Highest allocated VBN. The ACP maintains this field when the file is extended or truncated. Attempts to modify this field in a write attributes operation are ignored. FAT$W_HIBLKH High-order 16 bits FAT$W_HIBLKL Low-order 16 bits
FAT$L_EFBLK 2 3	End-of-file VBN FAT$W_EFBLKH High-order 16 bits FAT$W_EFBLKL Low-order 16 bits
FAT$W_FFBYTE 3	First free byte in FAT$L_EFBLK.
FAT$B_BKTSIZE	Bucket size in blocks.
FAT$B_VFCSIZE	Size in bytes of fixed-length control for VFC records.
FAT$W_MAXREC	Maximum record size in bytes.
FAT$W_DEFEXT	Default extend quantity.
FAT$W_GBC	Global buffer count.
FAT$W_VERSIONS	Default version limit; valid only if the file is a directory.

Figure 1-8 shows the format of the attributes statistics block. Table 1-10 lists the contents of this block.

Figure 1-8 ACP--QIO Attributes Statistics Block

Table 1-10 Contents of the Statistics Block

Field	Subfields	Meaning
SBK$L_STLBN		Contains the starting LBN of the file if the file is contiguous. If the file is not contiguous, this field contains a value of 0. The LBN appears as an inverted longword (the high- and low-order 16 bits are transposed for PDP-11 compatibility). The following subfields are defined:
	SBK$W_STLBNH	Starting LBN (high-order 16 bits)
	SBK$W_STLBNL	Starting LBN (low-order 16 bits)
SBK$L_FILESIZE		Contains the size of the file in blocks. The file size appears as an inverted longword (the high- and low-order 16 bits are transposed for PDP-11 compatibility). The following subfields are defined:
	SBK$W_FILESIZH	File size (high-order 16 bits)
	SBK$W_FILESIZL	File size (low-order 16 bits)
SBK$B_ACNT 1		Access count (low byte). Field is for PDP-11 compatibility.
SBK$B_LCNT 1		Lock count (low byte). Field is for PDP-11 compatibility.
SBK$L_FCB		System pool address of the file's file control block.
SBK$W_ACNT 1		Access count (number of channels with file open currently).
SBK$W_LCNT 1		Lock count (the number of access operations that have locked the file against writers).
SBK$W_WCNT 1		Writer count (the number of channels that currently have the file open for write).
SBK$W_TCNT 1		Truncate lock count (the number of access operations that have locked the file against truncation).
SBK$L_READS		Number of read operations executed for the file on this channel.
SBK$L_WRITES		Number of write operations executed for the file on this channel.

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