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1. Commands and Utilities v3

Product Information

Environment Specification

Temporary Waivers

1.1 POSIX.2 Supported Features

Question 1: Which of the following options, specified in the <unistd.h> header, are available on the system?

Response

Macro Name	Meaning	Provided
_POSIX2_C_BIND	Implementation supports the C language binding option.	Yes
_POSIX2_C_DEV	Implementation supports the C language development utilities option.	Yes
_POSIX2_CHAR_TERM	Implementation supports at least one terminal type.	Yes
_POSIX2_FORT_DEV	Implementation supports the FORTRAN Development Utilities Option.	No
_POSIX2_FORT_RUN	Implementation supports the FORTRAN Run-time Utilities.	No
_POSIX2_LOCALEDEF	Implementation supports the creation of locales by the localedef utility.	Yes
_POSIX2_SW_DEV	Implementation supports the Software Developments Utilities Option.	Yes
_POSIX2_UPE	Implementation supports the User Portability Utilities Option.	Yes

Rationale

For a Commands and Utilities V3 conformant implementation, _POSIX2_C_BIND, _POSIX2_CHAR_TERM, _POSIX2_LOCALDEF and _POSIX2_UPE must be supported. The other constants identify optional functionality that an implementation may or may not choose to support.

Reference

CAE Specification, System Interfaces and Headers, Issue 5, Chapter 4, Headers, <unistd.h>.

1.2 Development Utilities

1.2.1 Supported Commands

Question 2: Which of the development utilities are not provided with the implementation?

Response

All development utilities are provided.

Rationale

The development utilities are required to exist on designated DEVELOPMENT systems but may not be present on all XSI-conformant systems. The dis utility is defined as optional and need not be present even on systems that support the remainder of the development utilities.

Reference

CAE Specification, Commands and Utilities, Issue 5, Section 1.3.1, Optional, and Section 1.3.2, Development.

1.3 FORTRAN Option

1.3.1 FORTRAN Utility

Question 3: Is the FORTRAN fort77 utility provided?

Response

No

Rationale

The fort77 utility is the command level interface to the FORTRAN compiler, which need not be provided.

Reference

CAE Specification, Commands and Utilities, Issue 5, Section 1.3.3, FORTRAN.

1.4 Possibly Unsupportable Utilities and Options

Question 4: Which of the following utilities and utility options are not supported on the implementation?

Response

Utility	Option	Supported
ar	-s	Yes
lp	-m	Yes
	-o	No
	-t	Yes
	-w	Yes
sort	-z	Yes
tabs	+m	Yes
uucp	-C	Yes
	-f	Yes
	-j	Yes
	-n	Yes
	-r	Yes
uustat	-q	Yes
	-r	Yes
uux	-j,--	Yes

Rationale

A number of utilities and utility options are marked as possibly unsupportable features, and the functionality associated with these need not be present in a conforming implementation.

Reference

CAE Specification, Commands and Utilities, Issue 5, Section 1.7, Portability.

1.5 Legacy Option

Question 5: Which of the following Legacy utilities are provided?

Response

Some of the Legacy utilities are provided and listed below.

Rationale

The Legacy utilities are optional on XSI-conformant systems.

Reference

CAE Specification, Commands and Utilities, Issue 5, Section 1.3, LEGACY.

1.6 Specific Commands and Utilities

1.6.1 at

Question 6: How does the at command interpret a non-null SHELL environment variable?

Response

Uses sh irrespective of the setting of SHELL.

Rationale

The interpretation of the SHELL environment variable can cause at to invoke different versions of the shell on some implementations.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, at, ENVIRONMENT VARIABLES, SHELL.

1.6.2 awk

Question 7: What is the limit on the number of open streams provided by awk?

Response

4096 open streams.

Rationale

The number of open streams that are available to awk may differ between implementations, possibly depending on the number of streams that are available to a process ({FOPEN_MAX}).

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, awk, Input/Output and General Functions, close().

1.6.3 batch

Question 8: How does the batch command interpret a non-null SHELL environment variable?

Response

Uses sh irrespective of the setting of SHELL.

Rationale

The interpretation of the SHELL environment variable can cause batch to invoke different versions of the shell on some implementations.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, batch, ENVIRONMENT VARIABLES, SHELL.

1.6.4 c89

Question 9: Which defined names are automatically provided by the compiler?

Response

__LANGUAGE_C__ __unix__ __osf__ __alpha _SYSTYPE_BSD _LONGLONG __digital__ __arch64__

Rationale

The automatic provision of defined names by the compiler can cause these names to be unavailable in the name space for defined names.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, c89, OPTIONS, -D.

Question 10: When multiple input files are specified, where does c89 direct identification messages designating the start of each input file processing?

Response

Standard error.

Rationale

These messages, if produced, must be written to one or the other of standard output and standard error, but not to both. The destination of these messages is useful in determining redirections that are necessary to identify the input files from which warning messages are generated.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, c89, STDOUT and STDERR.

Question 11: What are the limits associated with external symbols imposed by c89?

Response

Description	Minimum Maximum	Implementation Maximum
Number of significant bytes	31	1023
Number of external symbols per source or object file	511	1023
Total number of external symbols	4095	No fixed limit

Rationale

These limits vary between implementations and cannot be reset by the user. The XCU definition gives the minimum maximum value for each of the values. Some applications may require larger limits than these minimum maxima.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, c89, EXTENDED DESCRIPTION, External Symbols.

1.6.5 cp

Question 12: What is the affect of alternate access control mechanisms on file copies?

Response

The Access Control List (ACL) function, if enabled, may prevent the cp command from accessing files to be copied. ACL are disabled by default. ACL functionality is described in the ACL Manpage.

Rationale

Because of the additional restrictions on creating files and reading data from files, the cp utility may not behave as described when alternate access control mechanisms are in use.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, cp, DESCRIPTION (final paragraph).

1.6.6 date

Question 13: Does date permit the setting of the date and time?

Response

Yes

Rationale

Some systems, particularly those that are hosted as part of a total system environment, do not allow the date command to set the date. On such systems, the setting of the date can only be accomplished from the host environment.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, date, OPERANDS, mmddhhmm[yy].

1.6.7 ex

Question 14: What restrictions are imposed on the set of commands within the rhs of the map command?

Response

A maximum of 128 map macros can be defined with a 2048 Byte total.

Rationale

Implementations may impose restrictions on the commands that can be used by macros in visual mode.

Reference

CAE Specifications, Commands and Utilities, Issue 5, Chapter 3, Utilities, ex, EXTENDED DESCRIPTION, Command Descriptions in ex, Map.

1.6.8 fc

Question 15: Is the history list mechanism disabled for users with appropriate privileges who do not set HISTFILE?

Response

No

Rationale

The specification states that an implementation may, in certain circumstances, disable the history list mechanism for users with appropriate privileges who do not set HISTFILE. This could have some security implications.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, fc, ENVIRONMENT VARIABLES, HISTFILE.

1.6.9 fort77

Question 16: When multiple input files are specified, where does fort77 direct identification messages designating the start of each input file processing?

Response

Not applicable.

Rationale

These messages, if produced, must be written to one or the other of standard output and standard error, but not to both. The destination of these messages is useful in determining redirections that are necessary to identify the input files from which warning messages are generated. If the response is not applicable then the fort77 utility is not supported.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, fort77, STDERR.

Question 17: What are the limits associated with external symbols imposed by fort77?

Response

Description	Minimum Maximum	Implementation Maximum
Number of significant bytes	31	N/A
Number of external symbols per source or object file	511	N/A
Total number of external symbols	4095	N/A

Rationale

These limits vary between implementations and cannot be reset by the user. The specification gives the minimum maximum value for each of the values. Some applications may require larger limits than these minimum maxima. If the responses are not supported then the fort77 utility is not supported.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, fort77, EXTENDED DESCRIPTION, External Symbols.

1.6.10 lex

Question 18: Where are error messages sent when the lex -t option is not specified?

Response

Standard output.

Rationale

These messages can be directed to either standard output or standard error, though the messages are not allowed to be directed to both. An application may wish to redirect these messages to a file.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, lex, STDOUT.

1.6.11 ln

Question 19: Can ln create links to a directory?

Response

No

Rationale

Implementations may disallow the creation of hard links to a directory, even though the executing process has the appropriate privileges.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, ln, OPERANDS, source_file.

1.6.12 localedef

Question 20: What is the default character mapping used when the localedef -f option is not specified?

Response

The default is ISO8859-1

Rationale

The specification does not define a specific character mapping as the default for conforming systems. This character mapping provides encoding information for the members of the portable character set.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, localedef, OPTIONS, -f.

1.6.13 lp

Question 21: What lp option or operator command is used to suppress the printing of a banner page?

Response

lp -o nobanner

Rationale

The user may require that banner pages are suppressed in cases where pre-printed forms are used and the stationary is of a non-standard length.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, lp, DESCRIPTION.

1.6.14 ls

Question 22: How many bytes are in a block as reported by ls?

Response

1024

Rationale

The block size used by ls to report the number of blocks occupied by a file varies from system to system; often this depends on the underlying file system architecture.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, ls, OPTIONS, -s.

1.6.15 make

Question 23: What additional variables does make add to its environment?

Response

MAKE, AR, AS, ARFLAGS, ASFLAGS, YACC, YFLAGS, LEX, LFLAGS, LDFLAGS, LOADLIBES, CC, CP, CPFLAGS, CFLAGS, FC, F90C, FFLAGS, GET, GFLAGS, SCCSFLAGS, SCCSGETFLAGS

Rationale

The implementation of make may set certain environment variables on invocation of make. These variables may not be set by the user, thus reducing the name space for environment variables.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, make, EXTENDED DESCRIPTION, Makefile Execution.

Question 24: Does the default MAKEFLAGS environment variable contain additional implementation-dependent options?

Response

MAKEFLAGS is not defined by default. It is a user definable variable and if defined is used by make.

Rationale

The implementation of make may set certain default MAKEFLAGS options on invocation of make. These variables are in addition to those set by the user on the command line and could affect the processing of make.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, make, EXTENDED DESCRIPTION, Makefile Execution.

1.6.16 newgrp

Question 25: Does newgrp allow users who are not listed as a member of a group which has no password to change to that group?

Response

No

Rationale

On some implementations, a user who is not listed as a member of a group may change to that group in the case that there is no password associated with the group.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, newgrp, DESCRIPTION.

Question 26: Are there any other implementation-specific authorisation restrictions that affect newgrp?

Response

Only a user with superuser authorization can change the primary group of the shell process to one to which that user does not belong.

Rationale

Some implementations may impose accounting or other restrictions that could cause newgrp to deny activity to a group member. For example, a resource quota system could be implemented on a group basis that would limit the ability to join a group until the resources were available to the group.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, newgrp, DESCRIPTION.

1.6.17 nice and renice

Question 27: What are the limits and default values used by nice and renice?

Response

Maximum nice value	19
Minimum nice value	-10
Default nice value	10

Rationale

Each of these values differs between implementations and the range of values gives the user some control over the relative priority of processes.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, nice, DESCRIPTION.

1.6.18 pax

Question 28: What is the default archive format used by pax?

Response

Extended tar interchange format.

Rationale

The implementation has the choice as to which format it shall use as the default when it is creating files. When it is reading an archive created in either extended tar or extended cpio format (or any other format that it understands), the pax utility will read the archive in the format as written.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, pax, DESCRIPTION.

Question 29: How does pax handle reading and writing of archives that span multiple files?

Response

The user is prompted for the next archive file, in the traditional manner of cpio.

Rationale

In many cases pax will take actions, such as prompting the user for the device name to use for the next archive file, when the current archive file is full. There may be extensions to the syntax of pax which allow the user to specify the address to use to access subsequent files.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, pax, DESCRIPTION.

Question 30: How does pax handle invalid filenames when it is extracting files from an archive?

Response

An error is issued indicating that the file is ignored, processing continues.

Rationale

An implementation may either extract the data associated with these files into files named in an implementation-defined manner or may issue an error indicating that the file is being ignored. If pax extracts the file, it is necessary for the user either to be informed of the file that is used or to know the algorithm that pax uses in generating these filenames.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, pax, EXTENDED DESCRIPTION, The cpio Filename.

1.6.19 printf

Question 31: Does printf support the e, E, f, g and G floating point conversion specifications?

Response

Yes

Rationale

The support of these conversions is optional.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, printf, EXAMPLES.

1.6.20 sh

Question 32: Is the environment variable IFS ignored when the shell is invoked?

Response

Yes

Rationale

The specification allows that the sh command ignore the setting of the IFS environment variable on invocation. The setting of this variable has been used to breach security on systems which use the shell to interpret a call to the system() and execvp() interfaces.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, sh, ENVIRONMENT VARIABLES, IFS.

1.6.21 touch

Question 33: What is the latest date after the Epoch that can be used by touch?

Response

Tue Jan 19 03:14:07 2038 UTC

Rationale

Because of the limitations on the storage of times in the stat structure associated with a file, there is a limitation on the valid dates that can be specified to touch. This is directly related to the value that can be stored in the integral type time_t.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, touch, OPTIONS, -t.

1.6.22 yacc

Question 34: What are the limits of yacc's internal tables?

Response

Description	Minimum Maximum	Implementation Maximum
Number of tokens	126	3000
Number of non-terminals	200	1000
Number of rules	300	2000
Number of states	600	5000
Length of rules	5200	40000
Number of actions	4000	70000

Rationale

These internal table sizes vary between implementations and cannot be reset by the user. The specification gives the minimum maximum value for each of the table values.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, yacc, EXTENDED DESCRIPTION, Limits.

1.7 C-language Programming Environments

1.7.1 Supported Environments

Question 35: What C-language programming environments are provided?

Response

Programming Environment	Provided
The implementation provides a C-language programming environment with 32-bit int, long, pointer and off_t types.	No
The implementation provides a C-language programming environment with 32-bit int, long and pointer types and an off_t type using at least 64 bits.	No
The implementation provides a C-language programming environment with 32-bit int, and 64-bit long, pointer and off_t types.	Yes
The implementation provides a C-language programming environment with int using at least 32-bits, and long, pointer and off_t types using at least 64 bits.	No

Rationale

Commands and Utilities, Issue 5 defines these scenarios as possible C-language programming environment offerings.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, c89,

1.7.2 Default Environment

Question 36: What C-language programming environment is the default?

Response

The implementation provides a C-language programming environment with 32-bit int, and 64-bit long, pointer and off_t types.

Rationale

Commands and Utilities, Issue 5 specifies that one of these must be supported as the default.

Reference

CAE Specification, Commands and Utilities, Issue 5, Chapter 3, Utilities, c89,

Copyright © 2001 Compaq Computer Corporation
All rights reserved.

2. Change History

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