ISO/IEC TR 24715:2006

Overview

ISO/IEC TR 24715:2006 is a Type 3 Technical Report from ISO that documents and analyzes conflicts between ISO/IEC 9945 (POSIX) and the Linux Standard Base (LSB, ISO/IEC 23360). Based on LSB Core Specification 3.1 and POSIX (ISO/IEC 9945:2003 with corrigendum), the report lists differences in system interfaces, shell and utilities, and provides background on POSIX and LSB. Its purpose is to help standards workgroups and implementers identify incompatibilities that affect portability and interoperability between POSIX-conformant applications and LSB-conformant Linux systems.

Key Topics

The report focuses on practical, implementable differences that can cause runtime or build-time incompatibilities:

• Headers and errno values
  • Example: LSB maps ENOTSUP to EOPNOTSUP, while POSIX requires unique errno values.
• File-control flags
  • Behavior of O_LARGEFILE and when implementations may set it (environment-dependent).
• Formatted I/O and scanf/fscanf
  • LSB defines a length-modifier a for string allocation that conflicts with ISO C99’s %a (hexadecimal floating).
• Command-line parsing
  • getopt(): LSB mandates GNU extensions (argument reordering); POSIX behavior is available via POSIXLY_CORRECT.
• Process and signal semantics
  • kill(-1, sig): LSB excludes the calling process, differing from POSIX wording.
• Filesystem behavior
  • link() and symbolic-link resolution differences; unlink() may return EISDIR on some LSB systems vs EPERM in POSIX.
• Error-message APIs
  • strerror_r() return type and behavior differences (char * vs int).
• Time parsing
  • strptime() handling of excessive leading zeros may vary.
• Process-wait semantics
  • waitpid() and optional support for WCONTINUED/WIFCONTINUED; waitid() absent from LSB.

The report distinguishes possible conflicts, upward-compatible extensions, and optional versus mandatory interfaces.

Applications and Audience

This Technical Report is intended for:

• Standards workgroups (the Austin Group, LSB workgroup) for harmonization and defect reporting
• Systems engineers and porting teams assessing application portability between POSIX and LSB
• Software developers writing portable system-level code
• Technical managers and procurement officers evaluating conformance and interoperability requirements

Use cases:

• Preparing porting guides and compatibility matrices
• Deciding conformance targets for commercial Linux distributions
• Identifying test cases for interoperability testing between POSIX and LSB

Related Standards

• ISO/IEC 9945 (POSIX) - base definitions, system interfaces, shell & utilities
• ISO/IEC 23360 - Linux Standard Base (LSB) Core Specification 3.1

Keywords: POSIX, LSB, Linux Standard Base, ISO/IEC 24715, system interfaces, shell and utilities, portability, interoperability, errno, strerror_r, strptime, getopt, waitpid.