Introduction

This page is aimed at both Debian and upstream developers, talking about things to keep in mind when developing a program or packaging it so that it remains portable.

Contents

  1. Introduction
  2. See also
  3. Cross Compiling
    1. Terminology
    2. Package Build
    3. Building and Running Tools
  4. Best Practices
    1. Autoconf and Automake
  5. Programming Considerations
    1. Integral Types
    2. Endianness
    3. Alignment
    4. Floating Point Behaviour
    5. Page Sizes
  6. Feature vs System detection
    1. System detection (usually wrong)
      1. config.{guess,sub}
      2. uname
      3. CPP system macros
      4. Other system checks ...
    2. Check for specific functionality (good)
  7. Build Failures
    1. Unportable ioctls
    2. Limiting macros
    3. Optional POSIX features
    4. Kernel/System dependencies
  8. Runtime Failures
    1. /proc
    2. /sys
    3. devfs on kFreeBSD
    4. Missing kernel features
    5. Hardcoded values instead of using macros
    6. Making dirs ending with a slash '/'

See also

Cross Compiling

Terminology

Host
The system the software is being compiled on. In GNU terminology, this is the "build" system.
Target
The system the software will run on. GNU calls this "host".

Package Build

($DEB_BUILD_ARCH, $DEB_HOST_ARCH & co.)

Building and Running Tools

Best Practices

Autoconf and Automake

(how to build a toplevel project)

Programming Considerations

(Link to ArchitectureSpecificsMemo?)

Integral Types

Endianness

Alignment

Floating Point Behaviour

Page Sizes

Feature vs System detection

System detection (usually wrong)

config.{guess,sub}

uname

CPP system macros

Other system checks ...

Check for specific functionality (good)

(autoconf)

Build Failures

Unportable ioctls

Limiting macros

(PATH_MAX and friends)

Optional POSIX features

Kernel/System dependencies

(linuxisms: mount, linuxthreads abuse) (bsdisms: sys_errlist[] vs. strerror())

Runtime Failures

/proc

/sys

devfs on kFreeBSD

(some nodes are not allowed on FreeBSD's devfs)

Missing kernel features

(sysv shm)

Hardcoded values instead of using macros

(open())

Making dirs ending with a slash '/'

CategoryEmdebian