3.7 Finding recommended ISO C and POSIX function substitutes
Gnulib contains a wealth of portability workarounds for ISO C and POSIX
functions. They are listed in detail in the chapter ISO C and POSIX Function Substitutes.
If you want to know which function substitutes are recommended for your
package, you can search your source code for ISO C and POSIX functions
that it uses and read the corresponding sections of said documentation
chapter. But this is a tedious task. Here is an alternative approach
that makes this task easier.
- Add the Gnulib module ‘posixcheck’ to the Gnulib imports of your package,
as described earlier in this chapter.
- Do a
make distclean if you previously built in the top-level directory.
Then regenerate the Autotools-generated parts of the package.
- On a glibc system, build your package. Pay attention to the compiler warnings.
Warnings are generated for uses of ISO C and POSIX functions that have
portability problems or other important pitfalls and for which you have not yet
imported the corresponding Gnulib module. If you get, say, a warning
“warning: call to ’close’ declared with attribute warning: close does not
portably work on sockets - use gnulib module close for portability”,
put ‘close’ on your list of modules to import.
- Add the modules you noted to the Gnulib imports of your package.
- Optionally, you can do the same steps again, and make sure that there are no
warnings left except those that you want to intentionally ignore.
- Finally, remove the Gnulib module ‘posixcheck’ from the Gnulib imports,
and run
make distclean.