Resources for Portable Programming

This page is a set of pointers to useful references for writing good portable code, for the R developers and for people writing R extensions.

C99 standard (technically a final draft: currently unavailable, but this appears to be a corrected version). And its rationale.
C11 standard (technically a final draft), and an overview of the changes.
Fortran standards, including links to the F77 as well as the correct layout of Fortran 77 subprograms. Final draft standards are available for F90 and F2003.
ftnchek, a program to check against Fortran standards.
POSIX 1003 standards (2008, revised 2018): how Unix-alike functions and tools are to behave. (2004 edition).
Porting to 64 bit GNU/Linux systems. Covers a lot of details about 64- vs 32-bit architectures.
The self-styled Filesystem Hierarchy Standard. Not written to the standard of a standard, but Debian Linux policy.
How to write shared libraries. Lots of information on GCC 4.0.0 features, including controlling symbol visibility as implemented in R 2.3.0.
mudflap. A bounds-checking (etc) tool for GCC 4.
Valgrind. A debugging tool for ix86 Linux. (See also `Writing R Extensions'.)
GCC Links and selected readings
What Every Computer Scientist Should Know about Floating-Point Arithmetic by David Goldberg, including Doug Priest's supplement on extended-precision systems (such as ix86).
FreeBSD's collection of man pages (including for some commercial Unixes). And more from *nixDoc.
Jan Walter's Unix incompatibility notes. Not 100% reliable (please don't pretest isalpha by isascii, for example).