1.6 Major Functions
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The following sections describe the operation of the major ACP functions. Each section describes the required and optional parameters for a particular function, as well as the sequence in which the function is performed. For clarity, when a major function invokes a subfunction, the input parameters used by the subfunction are omitted.
Create file is a virtual I/O function that creates a directory entry or a file on a disk device, or a file on a magnetic tape device.
The following is the function code:
The following are the function modifiers:
IO$M_ACCESS—Opens the file on your channel.
IO$M_DELETE—Marks the file for deletion (applicable only to disk devices).
The following are the device- or function-dependent arguments for IO$_CREATE:
P1—The address of the file information block (FIB) descriptor.
P2—The address of the file name string descriptor (optional).
P3—The address of the word that is to receive the length of the resultant file name string (optional).
P4—The address of a descriptor for a buffer that is to receive the resultant file name string (optional).
P5—The address of a list of attribute descriptors (optional).
Table 1-11 lists fields in the FIB that are applicable to the IO$_CREATE operation.
Table 1-11 IO$_CREATE and the FIB
Field | Subfields | Meaning |
|---|---|---|
FIB$L_ACCTL | Specifies field values that control access to the file. The following bits are applicable to the IO$_CREATE function: | |
FIB$V_REWIND | Set to rewind magnetic tape before creating the file. Any data currently on the tape is overwritten. | |
FIB$V_CURPOS | Set to create magnetic tape file at the current tape position. (Note: a magnetic tape file is created at the end of the volume set if neither FIB$V_REWIND nor FIB$V_CURPOS is set.) If the tape is not positioned at the end of a file, FIB$V_CURPOS creates a file at the next file position. Any data currently on the tape past the current file position is overwritten. | |
FIB$V_WRITETHRU | Specifies that the file header is to be written back to the disk. If not specified and the file is opened, writing of the file header can be deferred to some later time. | |
FIB$W_CNTRLFUNC | Specifies the following value, which allows you to control actions subsequent to EOT detection on a magnetic tape file. | |
FIB$W_FID | Contains the file ID of the file created or entered. | |
FIB$W_DID | Contains the file identifier of the directory file. | |
FIB$W_NMCTL | Controls the processing of the file name in a directory operation. The following bits are applicable to the IO$_CREATE function: | |
FIB$V_NEWVER | Set to create a file of the same name with the next higher version number. Only for disk devices. | |
FIB$V_SUPERSEDE | Set to supersede an existing file of the same name, type, and version. Only for disk devices. | |
FIB$V_LOWVER | Set on return if a lower numbered version of the file exists. Only for disk devices. | |
FIB$V_HIGHVER | Set on return if a higher numbered version of the file exists. Only for disk devices. | |
FIB$W_VERLIMIT | Specifies the version limit for the directory entry created. Used only for disk devices and only when the first version of a new file is created. If 0, the directory default is used. If a directory operation was performed, FIB$W_VERLIMIT always contains the actual version limit of the file. | |
FIB$L_ACL_STATUS | Status of the requested ACL attribute operation, if any. The ACL attributes are included in Table 1-7. If no ACL attributes are given, SS$_NORMAL is returned here. | |
FIB$L_STATUS | Access status. Programmers can control the security information being propagated as well as the source of this information by setting the following bits. |
If the modifier IO$M_CREATE is specified, a file is created. The file ID of the file created is returned in FIB$W_FID. If the modifier IO$M_DELETE is specified, the file is marked for deletion.
If a non-zero directory ID is specified in FIB$W_DID, a directory entry is created. The file name specified by parameter P2 is entered in the directory, together with the file ID in FIB$W_FID. (Table 1-2 describes the format for the file name string.) Wildcards are not permitted. Negative version numbers are treated as equivalent to a 0 version number. If a result string buffer and length are specified by P3 and P4, the actual file name entered, and its length, are returned.
The version number of the file receives the following treatment:
If the version number in the specified file name is 0 or negative, the directory entry created gets a version number one greater than the highest previously existing version of that file (or version 1 if the file did not previously exist).
If the version number in the specified file name is a nonzero number and FIB$V_NEWVER is set, the directory entry created gets a version number one greater than the highest previously existing version of that file, or the specified version number, whichever is greater.
If the version number in the specified file name is a nonzero number and the directory already contains a file of the same name, type, and version, the previously existing file is set aside for deletion if FIB$V_SUPERSEDE is specified. If FIB$V_SUPERSEDE is not specified, the create operation fails with a SS$_DUPFILNAM status.
If, after creating the new directory entry, the number of versions of the file exceeds the version limit, the lowest numbered version is set aside for deletion.
If the file did not previously exist, the new directory entry is given a version limit as follows: the version limit is taken from FIB$W_VERLIMIT if it is a nonzero number; if it is 0, the version limit is taken from the default version limit of the directory file; if the default version limit of the directory file is 0, the version limit is set to 32,767 (the highest possible number).
The file name string entered in the directory is returned using the P3 and P4 result string parameters, if present. The file name string is also written into the header. If no directory operation is requested (FIB$W_DID is 0), the file name string specified by P2, if any, is written into the file header.
If an attribute list is specified by P5, a write attributes subfunction is performed (see “Read/Write Attributes”).
If the modifier IO$M_ACCESS is specified, the file is opened (see “Access”).
If the extend enable bit FIB$V_EXTEND is specified in the FIB, an extend subfunction is performed (see “Extend”).
Finally, if a file was set aside for deletion (IO$M_DELETE is specified), that file is deleted. If the file is deleted because the FIB$V_SUPERSEDE bit was set, the alternate success status SS$_SUPERSEDE is returned in the I/O status block. If the file is deleted because the version limit was exceeded, the alternate success status SS$_FILEPURGED is returned.
If an error occurs in the operation of an IO$_CREATE function, all actions performed to that point are reversed (the file is neither created nor changed), and the error status is returned to the user in the I/O status block.
Creating a new version of a file eliminates default access to the previously highest version of the file. For example, creating RESUME.TXT;4 masks RESUME.TXT;3 so the DCL command TYPE RESUME.TXT yields the contents of version 4, not version 3. To protect the contents of the earlier version of a file, the creator of a file must have write access to the previous version of a file of the same name.
No operation is performed unless the IO$M_CREATE modifier is specified. The magnetic tape is positioned as specified by FIB$V_REWIND and FIB$V_CURPOS, and the file is created. The name specified by the P2 parameter is written into the file header label.
If P5 specifies an attribute list, a write attributes subfunction is performed (see “Read/Write Attributes”).
If the modifier IO$M_ACCESS is specified, the file is opened (see “Access”).
This virtual I/O function searches a directory on a disk device or a magnetic tape for a specified file and accesses that file if found.
The following is the function code:
The following are the function modifiers:
The following are the device- or function-dependent arguments for IO$_ACCESS:
P1—The address of the file information block (FIB) descriptor.
P2—The address of the file name string descriptor (optional).
P3—The address of the word that is to receive the length of the resultant file name string (optional).
P4—The address of a descriptor for a buffer that is to receive the resultant file name string (optional).
P5—The address of a list of attribute descriptors (optional).
Table 1-12 lists FIB fields that are applicable to the IO$_ACCESS operation.
Table 1-12 IO$_ACCESS and the File Information Block
Field | Subfields | Meaning |
|---|---|---|
FIB$W_ CNTRLFUNC | Specifies the value that allows the user to control actions subsequent to EOT detection on a magnetic tape file. | |
FIB$W_VERLIMIT | Receives the version limit for the file. Applicable only if FIB$W_DID is a nonzero number (if a directory lookup is done). Used only for disk devices. | |
FIB$L_ACL_STATUS | Status of the requested ACL attribute operation, if any. The ACL attributes are included in Table 1-7. If no ACL attributes are given, SS$_NORMAL is returned here. (For Files-11 C/D, this field is always set to SS$_NORMAL.) | |
FIB$L_STATUS | Alternate access status. The following bits are supported: | |
FIB$V_ALT_REQ | Set to indicate whether the alternate access bit is required for the current operation. If not set, the alternate access bit is optional. | |
FIB$V_ALT_GRANTED | If FIB$V_ALT_REQ = 0 and the alternate access check succeeded, the FIB bit returned from the file system is set. | |
FIB$L_ALT_ACCESS | A 32-bit mask that represents an access mask to check against file protection; for example, to open a file for read and to check whether it can be deleted. The mask has the same configuration as the standard protection mask. |
If a nonzero directory file ID is specified in FIB$W_DID, a lookup subfunction is performed (see “Directory Lookup”.) The version limit of the file found is returned in FIB$W_VERLIMIT.
If the directory search fails with a “file not found” condition and the IO$M_CREATE function modifier is specified, the function is reexecuted as a CREATE. In that case, the argument interpretations for IO$_CREATE, rather than those for IO$_ACCESS, apply.
If IO$M_ACCESS is specified, an access subfunction is performed to open the file (see “Access”).
If P5 specifies an attribute list, a read attributes subfunction is performed (see “Read/Write Attributes”).
Deaccess file is a virtual I/O function that deaccesses a file and, if specified, writes final attributes in the file header.
The following is the function code:
IO$_DEACCESS takes no function modifiers.
The following are the device- or function-dependent arguments for IO$_DEACCESS:
P1—The address of the file information block (FIB) descriptor.
P5—The address of a list of attribute descriptors (optional).
The following FIB fields are applicable to the IO$_DEACCESS function:
Field | Meaning |
|---|---|
FIB$W_FID | File ID of the file being deaccessed. This field can contain a value of 0. If it does not, it must match the file identifier of the accessed file. |
FIB$L_ACL_STATUS | Status of the requested ACL attribute operation, if any. The ACL attributes are included in Table 1-7. If no ACL attributes are given, SS$_NORMAL is returned here. (For Files-11 C/D, this field is always set to SS$_NORMAL.) |
For disk files, if P5 specifies an attribute control list and the file was accessed for a write operation, a write attributes subfunction is performed (see “Read/Write Attributes”). If the file was opened for write, no attributes were specified, and FIB$V_DLOCK was set when the file was accessed, the deaccess lock bit is set in the file header, inhibiting further access to that file.
For disk files, if the truncate enable bit FIB$V_TRUNC is specified in the FIB, a truncate subfunction is performed (see “Truncate”).
Finally, the file is closed. Trailer labels are written for a magnetic tape file that was opened for write.
Modify file is a virtual I/O function that modifies the file attributes or allocation of a disk file. The IO$_MODIFY function is not applicable to magnetic tape; that is, the function returns success, but no action is performed.
The following is the function code:
The following is the function modifier:
The following are the device- or function-dependent arguments for IO$_MODIFY:
P1—The address of the file information block (FIB) descriptor.
P2—The address of the file name string descriptor (optional). If specified, the directory is searched for the name.
P3—The address of the word that is to receive the length of the resultant file name string (optional).
P4—The address of a descriptor for a buffer that is to receive the resultant file name string (optional).
P5—The address of a list of attribute descriptors (optional).
The following FIB fields are applicable to the IO$_MODIFY function:
Field | Subfields | Meaning |
|---|---|---|
| FIB$L_ACCTL | Specifies field values that control access to the file. The following bit is applicable to the IO$_MODIFY function: | |
| FIB$V_WRITETHRU | Specifies that the file header is to be written back to the disk. If not specified and the file is currently open, writing of the file header can be deferred to some later time. | |
| FIB$W_VERLIMIT | If a nonzero number, specifies the version limit for the file. | |
| FIB$L_ACL_STATUS | Status of the requested ACL attribute operation. The ACL attributes are listed in Table 1-7. If no ACL attributes are given, SS$_NORMAL is returned here. |
If a nonzero directory ID is specified in FIB$W_DID, a lookup subfunction is executed (see “Directory Lookup”). If a nonzero version limit is specified in FIB$W_VERLIMIT and the directory entry found is the latest version of that file, the version limit is set to the value specified.
If P5 specifies an attribute list, a write attributes subfunction is performed (see “Read/Write Attributes”).
The file can be either extended or truncated. If FIB$V_EXTEND is specified in the FIB, an extend subfunction is performed (see “Extend”). If FIB$V_TRUNC is specified in the FIB, a truncate subfunction is performed (see “Truncate”). Extend and truncate operations cannot be performed at the same time.
Delete file is a virtual I/O function that removes a directory entry or file header from a disk volume.
The following is the function code:
The following is the function modifier:
The following are the device- or function-dependent arguments for IO$_DELETE:
P1—The address of the file information block (FIB) descriptor.
P2—The address of the file name string descriptor (optional).
P3—The address of the word that is to receive the length of the resultant file name string (optional).
P4—The address of a descriptor for a buffer that is to receive the resultant file name string (optional).
The following FIB fields are applicable to the IO$_DELETE function:
Field | Subfields | Meaning |
|---|---|---|
FIB$L_ACCTL | Specifies field values that control access to the file. The following bits are applicable to the IO$_DELETE function: | |
FIB$V_NOLOCK (Alpha only) | Allows the caller to mark a file for delete that is currently open for write access. When the file is closed, it is automatically deleted. The file cannot be accessed by new callers after it has been marked for delete. | |
FIB$V_WRITETHRU | Specifies that the file header is to be written back to the disk. If not specified and the file is currently open, writing of the file header can be deferred to some later time. | |
FIB$W_DID | Contains the file identifier of the directory file. This field must be a nonzero number. | |
FIB$W_FID | Specifies the file identification to be deleted. |
If a nonzero directory ID is specified in FIB$W_DID, a lookup subfunction is performed (see “Directory Lookup”). The file name located is removed from the directory.
If the function modifier IO$M_DELETE is specified, the file is marked for deletion. If the file is not currently open, it is deleted immediately. If the file is open, it is deleted when the last accessor closes it.
The movefile subfunction permits you to move the contents of a file, or part of the contents of a file, to a new disk location. This subfunction can, for example, form the basis of a disk defragmentation application.
You can disable movefile operations on specific user files by specifying the /NOMOVE qualifier on the SET FILE command. Use the DIRECTORY/FULL and the DUMP/HEADER commands to find out if movefile operations are disabled on a file.
A program can invoke a movefile subfunction by issuing a QIO request using the function code IO$_MODIFY and the function modifier IO$M_MOVEFILE. This section describes the various input parameters that control the processing of movefile operations together with an operational description.
Table 1-13 lists the FIB fields that control the processing of a movefile subfunction.
Table 1-13 FIB Fields (Movefile)
Field | Subfields | Meaning |
|---|---|---|
FIB$L_ACCTL | Movefile control flag. The following flags are applicable: | |
FIB$V_NOVERIFY | Inhibits comparison of the moved blocks. If this flag is clear, the movefile operation verifies that the operation was carried out correctly by comparing the moved blocks to the original blocks. | |
FIB$V_CHANGE_VOL | Enables the movefile operation to move blocks from one volume to another within a volume set. The movefile operation clears this flag if the specified file is a directory. | |
FIB$W_FID | Specifies the file identification of the file to be moved. | |
FIB$W_EXCTL | Movefile control flags. The following flag applies to the movefile operation. All other FIB$W_EXCTL flags must be clear. | |
FIB$V_ALCON | Specifies that the movefile operation must allocate contiguous disk space to the moved blocks. If the necessary contiguous space is not available, the movefile operation fails. The movefile operation sets this flag if the file was previously marked as contiguous. | |
FIB$V_ALCONB | Specifies that the movefile operation should attempt to allocate contiguous disk space to the moved blocks. That is, if the movefile operation cannot allocate contiguous space to all the moved blocks, it allocates contiguous space to as many of the blocks as possible. The movefile operation sets this flag if the file was previously marked as contiguous best try. | |
FIB$V_FILCON | Specifies that the entire file must be made contiguous. Do not set this flag without also setting the FIB$V_ALCON flag. If the FIB$V_FILCON flag is set, and either the FIB$V_ALCON flag is clear or the file would not be made contiguous by moving the specified virtual blocks, the movefile operation fails. The movefile operation sets this flag if the file was previously marked as contiguous. | |
FIB$V_NOPLACE | Specifies that placement information is not recorded in the file header. If this flag is clear and you specify exact placement for the moved blocks, placement information for those blocks will be recorded in the file header. If this flag is set, the placement information is not recorded. You specify exact placement through the FIB$V_EXACT, FIB$C_LBN, and FIB$L_LOC_ADDR fields. | |
FIB$B_ALOPTS | Flags that control the placement of the allocated blocks. Currently, only the FIB$V_EXACT flag applies to the movefile operation. All other FIB$B_ALOPTS flags must be clear. The following flag is applicable: | |
FIB$V_EXACT | Set to require exact placement. If this flag is set and the specified blocks are not available, the movefile operation fails. | |
FIB$B_ALALIGN | Contains the interpretation mode of the allocation field (FIB$W_ALLOC). You can specify a field value of 0 or you can specify the symbolic value FIB$C_LBN. If you specify 0, the allocation field is ignored. | |
FIB$W_ALLOC | Contains the desired location of the blocks being allocated. Interpretation of the field is controlled by the FIB$B_ALALIGN field. The following subfields are defined: | |
FIB$B_LOC_RVN | Specifies the relative volume number (RVN) of the volume to which the blocks are moved. Do not specify a value for this field unless you have set the FIB$V_CHANGE_VOL flag. | |
FIB$L_LOC_ADDR | If the FIB$C_LBN and FIB$V_EXACT flags are set, specifies the starting logical address to which the blocks are moved. | |
FIB$L_MOV_SVBN | Specifies the virtual block number (VBN) of the first block to be moved. The starting VBN must correspond to the first block of a disk cluster. The value must be greater than 0 and it must not exceed the number of virtual blocks allocated to the file. If you specify an invalid value, the movefile operation fails. | |
FIB$L_MOV_VBNCNT | Specifies the number of consecutive virtual blocks to be moved. This value must be a multiple of the disk cluster size, and it must not exceed the difference between the greatest VBN allocated to the file and the FIB$L_MOV_SVBN value. If you specify a value of 0, the movefile operation moves all the virtual blocks between the FIB$L_MOV_SVBN value and the greatest VBN. If you specify an invalid value, the movefile operation fails. |
A program can perform a movefile operation on a file if the following conditions are met:
The program has write and control access to the file.
The file is closed.
Movefile operations are not disabled on the file.
Movefile operations are automatically disabled on critical system files. You can disable movefile operations on specific user files by specifying the /NOMOVE qualifier with the SET FILE command.
The operation is not interrupted.
If the movefile operation is interrupted by any other operation, such as a read or write operation, the movefile operation aborts and the file remains in its original position.
The movefile operation moves a specified number of consecutive virtual blocks to new logical blocks on disk, beginning with the virtual block specified in the FIB$L_SVBN field.
The number of blocks moved is specified in the FIB$L_VBNCNT field. To move an entire file, specify FIB$L_VBNCNT as 0 and FIB$L_SVBN as 1.
To specify a starting logical block for the moved blocks, specify the logical block address in the FIB$L_LOC_ADDR subfield and set the FIB$C_LBN and the FIB$V_EXACT flags.
To move the blocks to another volume, or move blocks that span more than one volume, set the FIB$V_CHANGE_VOL flag of the FIB$L_ACCTL field. Use the FIB$B_LOC_RVN subfield of the FIB$W_ALLOC field to specify the volume to which the blocks are moved. If you do not specify a volume, the blocks are moved to the volume containing the first virtual block. Note that you cannot move blocks of a directory file to another volume.
If the file was previously marked as contiguous, the movefile operation sets the FIB$V_ALCON, FIB$V_ALCONB, and FIB$V_FILCON flags. This ensures that a contiguous file is not fragmented by a movefile operation.
For virtual blocks beyond the file's highwater mark, the movefile operation allocates new logical blocks but does not copy the contents. The position of the file's highwater mark remains unchanged.
On Alpha and Integrity server systems, mount is a virtual I/O function that informs the ACP when a disk or magnetic tape volume is mounted. MOUNT privilege is required.
IO$_MOUNT takes no arguments or function modifiers. This function is part of the volume mounting operation only, and it is not meant for general use. Most of the actual processing is performed by the MOUNT command or the Mount Volume ($MOUNT) system service.
ACP Control is a virtual I/O function that performs ancillary control functions, depending on the arguments specified.
The following is the function code:
The following is the function modifier:
The following are the device- or function-dependent arguments for IO$_ACPCONTROL:
P1—The address of the file information block (FIB) descriptor.
P2—The address of the file name string descriptor (optional).
P3—The address of the word that is to receive the length of the resultant file name string (optional).
P4—The address of a descriptor for a buffer that is to receive the resultant file name string (optional).
Table 1-14 lists FIB fields that control the processing of the IO$_ACPCONTROL function.
Table 1-14 IO$_ACPCONTROL and the FIB
Field | Subfields | Meaning |
|---|---|---|
FIB$W_CNTRLFUNC | Specifies the control function to be performed. This field overlays FIB$W_EXCTL. | |
FIB$L_CNTRLVAL[1] | Specifies additional function-dependent data. This field overlays FIB$L_EXSZ. | |
FIB$L_ACL_STATUS | Status of the requested ACL attribute operation, if any. The ACL attributes are included in Table 1-7. If no ACL attributes are given, SS$_NORMAL is returned here. For Files-11 C/D, this field is always set to SS$_NORMAL. | |
FIB$L_STATUS[1] | Alternate access status. The following bits are supported: | |
FIB$V_ALT_REQ | Set to indicate whether the alternate access bit is required for the current operation. If not set, the alternate access bit is optional. | |
FIB$V_ALT_GRANTED | If FIB$V_ALT_REQ = 0 and the alternate access check succeeded, the FIB bit returned from the file system is set. | |
FIB$L_ALT_ACCESS[1] | A 32-bit mask that represents an access mask to check against file protection; for example, to open a file for read and to check whether it can be deleted or not. The mask has the same configuration as the standard protection mask. | |
[1] Not supported or valid for Files-11 C/D. | ||
Table 1-15 lists the FIB field applicable to magnetic tape operations.
Table 1-15 Magnetic Tape Operations and the FIB
Field | Subfields | Meaning |
|---|---|---|
FIB$W_CNTRLFUNC | Several ACP control functions are used for magnetic tape positioning. These functions are specified by supplying a FIB with P1 containing the FIB descriptor address. Modifiers and parameters P2, P3, and P4 are not allowed. These functions clear serious exceptions in magnetic tape drivers. The following control functions can be specified to control magnetic tape positioning: | |
FIB$C_REWINDFIL | Rewind to beginning-of-file. | |
FIB$C_REWINDVOL | Rewind to beginning-of-volume set. | |
FIB$C_POSEND | Position to end-of-volume set. | |
FIB$C_NEXTVOL | Force next volume. | |
FIB$C_SPACE | Space n blocks forward or backward. The FIB$L_CNTRLVAL field specifies the number of magnetic tape blocks to space forward if positive or to space backward if negative. | |
FIB$C_CLSEREXCP | If set, clears the serious exception in the magnetic tape driver (see FIB$C_USEREOT in “Create File” and “Access File”). If writing, allows you to write data blocks beyond the EOT marker, which can result in the magnetic tape not conforming to the ANSI standard for magnetic tapes (see ANSI Standard X3.27-1978). If reading, allows you to handle the move to the next volume or to stop reading the tape. Do not attempt to read past EOV. |
Several ACP control functions are available for disk volume control. The following function does not use parameters P2, P3, and P4:
The FIB$W_CNTRLFUNC field of the FIB specifies the following miscellaneous control functions (with no modifier on the IO$_ACPCONTROL function code). These functions use no other parameters.
FIB$C_REMAP | Remap a file. The file window for the file open on the user's channel is remapped so that it maps the entire file. |
FIB$C_LOCK_VOL | Allocation lock the volume. Operations that change the file structure, such as file creation, deletion, extension, and deaccess, are not permitted. If such requests are queued to the file system for an allocation-locked volume, they are not processed until the FIB$C_UNLK_VOL function is issued to unlock the volume. To issue the FIB$C_LOCK_VOL function, you must have either a system UIC or SYSPRV privilege, or be the owner of the volume. |
FIB$C_UNLK_VOL | Unlock the volume. Cancels FIB$C_LOCK_VOL. To issue this function, you must have either a system UIC or SYSPRV privilege, or be the owner of the volume. |
Disk quota enforcement is enabled by a quota file on the volume, or relative volume 1 if the file is on a volume set. The quota file appears in the volume's master file directory (MFD) under the name QUOTA.SYS;1. This section describes the control functions that operate on the quota file.
Table 1-16 lists the enable and disable quota control functions.
Table 1-16 Disk Quota Functions (Enable/Disable)
Value | Meaning |
|---|---|
FIB$C_ENA_QUOTA | Enable the disk quota file. If a nonzero directory file ID is specified in FIB$W_DID, a lookup subfunction is performed to locate the quota file (see “Directory Lookup”). To issue this function, you must have either a system UIC or SYSPRV privilege, or be the owner of the volume. The quota file specified by FIB$W_FID, if present, is accessed by the ACP, and quota enforcement is turned on. By convention, the quota file is named [0,0]QUOTA.SYS;1. Therefore, FIB$W_DID should contain the value 4,4,0 and the name string specified with P2 should be “QUOTA.SYS;1”. |
FIB$C_DSA_QUOTA | Disable the disk quota file. The quota file is deaccessed and quota enforcement is turned off. To issue this function, you must have either a system UIC or SYSPRV privilege, or be the owner of the volume. |
Table 1-17 lists the quota control functions that operate on individual entries in the quota file. Each operation transfers quota file data to and from the ACP using a quota data block. This block has the same format as a record in the quota file. Figure 1-7 shows the format of this block.
Table 1-17 Disk Quota Functions (Individual Entries)
Value | Meaning | |
|---|---|---|
| FIB$C_ADD_QUOTA | Add an entry to the disk quota file, using the UIC and quota specified in the P2 argument block. FIB$C_ADD_QUOTA requires write access to the quota file. | |
FIB$C_EXA_QUOTA | Examine a disk quota file entry. The entry whose UIC is specified in the P2 argument block is returned in the P4 argument block, and its length is returned in the P3 argument word. Using two flags in FIB$L_CNTRLVAL, it is possible to search through the quota file using wildcards. The two flags are: | |
FIB$V_ALL_MEM | Match all UIC members | |
| FIB$V_ALL_GRP | Match all UIC groups | |
The ACP maintains position context in FIB$L_WCC. On the first examine call, you specify 0 in FIB$L_WCC; the ACP returns a nonzero value so that each succeeding examine call returns the next matching entry. Read access to the quota file is required to examine all nonuser entries. | ||
| FIB$C_MOD_QUOTA | Modify a disk quota file entry. The quota file entry specified by the UIC in the P2 argument block is modified according to the values in the block, as controlled by the following three flags in FIB$L_CNTRLVAL: | |
FIB$V_MOD_PERM | Change the permanent quota | |
FIB$V_MOD_OVER | Change the overdraft quota | |
FIB$V_MOD_USE | Change the usage data | |
The usage data can be changed only if the volume is locked by FIB$C_LOCK_VOL (see “Miscellaneous Disk Control Functions”). FIB$C_MOD_QUOTA requires write access to the quota file. The P3 and P4 arguments return the modified quota entry to you. By using the flags FIB$V_ALL_MEM and FIB$V_ALL_GRP, you can search through the quota file using wildcards just as you would with the FIB$C_EXA_QUOTA function. | ||
FIB$C_REM_QUOTA | Remove a disk quota file entry whose UIC is specified in the P2 argument block. FIB$C_REM_QUOTA requires write access to the quota file. The P3 and P4 arguments return the removed quota file entry to you. By using the flags FIB$V_ALL_MEM and FIB$V_ALL_GRP, you can search through the quota file using wildcards just as you would with the FIB$C_EXAQUOTA function. | |
IO$_ACPCONTROL functions that transfer quota file data between the caller and the ACP use the following device- or function-dependent arguments: