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Enter the name of the Organization that produced the implementation and the name of the author of the Conformance Statement.

1. ISAM

Product Information

Environment Specification

Answer the questions for each binary-compatible family. Alternately, provide the answers in the Appendix at the end of this document.

	Testing Environment	Binary-compatible Family	Portability Environment	Indicator of Compliance	Compliance Details
			Select from this list Internationalised System Calls and Libraries Internationalised System Calls and Libraries Internationalised System Calls and Libraries Extended Internationalised System Calls and Libraries Extended V2	Select from this list Test Report from Test Suite	Test Suite: Test Report:
			Select from this list Internationalised System Calls and Libraries Internationalised System Calls and Libraries Internationalised System Calls and Libraries Extended Internationalised System Calls and Libraries Extended V2	Select from this list Test Report from Test Suite	Test Suite: Test Report:
			Select from this list Internationalised System Calls and Libraries Internationalised System Calls and Libraries Internationalised System Calls and Libraries Extended Internationalised System Calls and Libraries Extended V2	Select from this list Test Report from Test Suite	Test Suite: Test Report:
			Select from this list Internationalised System Calls and Libraries Internationalised System Calls and Libraries Internationalised System Calls and Libraries Extended Internationalised System Calls and Libraries Extended V2	Select from this list Test Report from Test Suite	Test Suite: Test Report:
			Select from this list Internationalised System Calls and Libraries Internationalised System Calls and Libraries Internationalised System Calls and Libraries Extended Internationalised System Calls and Libraries Extended V2	Select from this list Test Report from Test Suite	Test Suite: Test Report:

Temporary Waivers

1.1 Implementation Limits

Question 1: What limits does the implementation impose for the following aspects?

Response

For each entry in the table below, add the exact limit value applicable to your implementation. Note that "No Limit" is a valid response.

		Limit
1.	Number of key parts in an index (NPARTS)
2.	Maximum size of a key (MAXKEYSIZE)
3.	Maximum number of indices per file
4.	Maximum size of data record
5.	Maximum number of concurrently locked records
6.	Maximum number of ISAM files that can be concurrently open

Rationale

1. The ISAM specification states that the values for NPARTS and MAXKEYSIZE are implementation-specific but must be at least 8 and 120 respectively.
2. The ISAM specification states that the values for NPARTS and MAXKEYSIZE are implementation-specific but must be at least 8 and 120 respectively.
3. The ISAM specification puts no limit on the number of alternative indices that can be created for a file. However, some implementations impose a limit. The ISAM specification requires that an implementation support at least 15 alternate indices.
4. The ISAM specification does not specify the maximum length of a data record, though some implementations impose a limit.
5. The ISAM specification states that the number of records that may be concurrently locked when a file has been opened with ISMANULOCK set is implementation-dependent. This number may depend on the locks that are concurrently applied to other files and the number specified in the answer should be the maximum number of concurrently locked records that could be attained.
6. The ISAM specification states that an application program must be able to have at least ten ISAM files concurrently open. This limit assumes that the process has no other files open. The limit given in answer to the Question 1 must also be based upon this assumption.

Reference

X/Open Developers' Specification, Indexed Sequential Access Method (ISAM), Chapter 8, The <isam.h> Header, Section 4.1, Index Definition and Manipulation, Section 5.3.2, Manual Record Locking and Section 9.7, Files.

1.2 Variable-length Records

Question 2: Does the implementation support files having records of variable length?

Response

Yes   No

Rationale

The support of files which contain variable-length records is an optional facility in the ISAM specification. This facility will become mandatory in the next revision of the specification.

Reference

X/Open Developers' Specification, Indexed Sequential Access Method (ISAM), Section 9.8, Records.

Question 3: Does a variable-length record retain the same number after it is rewritten with a different length?

Response

Enter "Yes", "No", or "Variable". If you enter variable, enter a description of the manner in which variations occur.

Rationale

The ISAM specification states that it is implementation-defined whether the record number is retained. Some implementations retain the number when the size is diminished but not necessarily when it is extended.

Reference

X/Open Developers' Specification, Indexed Sequential Access Method (ISAM), Section 9.3, Record Number of Last Call.

Question 4: If the implementation does not support files with variable-length records does the setting of the ISVARLEN flag for isbuild(\|) and isopen(\|) generate an error?

Response

Yes No Not Applicable.

Rationale

The ISAM specification states that it is implementation-defined whether the record number is retained. On some implementations that do not support files with variable-length records, despite reporting an error when the application sets the ISVARLEN flag, the implementation retains the record number.

Reference

X/Open Developers' Specification, Indexed Sequential Access Method (ISAM), Section 9.3, Record Number of Last Call.

1.3 Locking

Question 5: Does an unsuccessful ISAM function call release a lock established by automatic record locking?

Response

Enter "Yes", "No", "or "Variable". If you enter variable, enter a description of the manner in which variations occur.

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Rationale

The ISAM specification states that it is implementation-defined whether an unsuccessful call releases a lock, though a successful call will always release the lock (except for a call to isstart(\|) with the ISKEEPLOCK flag set).

Reference

X/Open Developers' Specification, Indexed Sequential Access Method (ISAM), Section 5.3, Record Level Locking.

Question 6: Do the file locking operations islock(\|) and isunlock(\|) have effect when the file is opened in automatic locking mode?

Response

Yes   No

Rationale

The ISAM specification states that the effect of these calls is implementor-defined in the case that the file is opened with automatic locking enabled.

Reference

X/Open Developers' Specification, Indexed Sequential Access Method (ISAM), Section 5.5, Locking Matrix.

Question 7: Do record locks conflict when obtained by different processes using the same file descriptor?

Response

Yes   No

Rationale

The ISAM specification is silent on the locking behaviour when multiple processes use the same file descriptor. If a process forks off a child that makes use of a file descriptor opened by the parent, some implementations allow the child to access records that are locked by the parent and some don't.

Reference

X/Open Developers' Specification, Indexed Sequential Access Method (ISAM), Chapter 5, Locking.

Question 8: Do record locks conflict when obtained by the same process through different file descriptors?

Response

Yes   No

Rationale

The ISAM specification is silent on the locking behaviour when a single process accesses a file through multiple file descriptors. If a process opens two file descriptors, some implementations allow records locked using one file descriptor to be accessed through the other.

Reference

X/Open Developers' Specification, Indexed Sequential Access Method (ISAM), Chapter 5, Locking.

1.4 Threading

Question 9: Is your ISAM implementation thread safe?

Response

Yes No Partially.

Rationale

The ISAM specification is silent on the behaviour of multi-threaded applications. There are three possible answers:

1. Yes, the ISAM implementation is 100% thread safe. This indicates that multiple threads can make use of any feature in the interface without interfering with each other, including the use of global variables.
2. The ISAM implementation is partially thread safe. This indicates that multiple threads can use the interface, but use of some features may cause interference between different threads. This is the case if the functions themselves are thread safe, but the global variables are not.
3. No, the ISAM implementation is not thread safe. This answer indicates that if multiple threads were to use the interface, highly incorrect or pathological behaviour may ensue. This is the case if multiple threaded use of the interface may cause the process to be killed or incorrect data to be seen by the application.

Reference

X/Open Developers' Specification, Indexed Sequential Access Method (ISAM).

2. Appendix

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3. Change History