strftime (GNU Gnulib)

Gnulib module: strftime-fixes

Portability problems fixed by Gnulib:

On native Windows platforms (mingw, MSVC), this function works incorrectly when the environment variable TZ has been set by Cygwin.

Portability problems not fixed by Gnulib:

The %c specifier does not work with a time retrieved through gmtime or gmtime_r, since it outputs also the current time zone, on some platforms: glibc 2.30, NetBSD 10.0, Solaris 11.4.
The %c specifier produces no weekday name and no month name, only a potentially ambiguous numerical output, on some platforms: mingw, MSVC.
The %h specifier produces empty output on some platforms: mingw, MSVC.
The %r specifier produces empty output on some platforms: mingw, MSVC.
The %r specifier produces empty output, at least in a French locale, on some platforms: macOS 12.5, FreeBSD 14.0.
The %r specifier includes an AM/PM indicator, at least in a French locale, on some platforms: NetBSD 10.0, Solaris 11.4.
The %p specifier produces non-empty output, at least in a French locale, on some platforms: NetBSD 10.0, Solaris 11.4.
The Windows C runtime library (which is used by MinGW) does not support the %e specifier (and possibly the other more recent SUS specifiers too, i.e., %C, %D, %h, %n, %r, %R, %t, and %T).
Native Windows platforms (mingw, MSVC) support only a subset of time zones supported by GNU or specified by POSIX. See tzset.

Extension: Gnulib offers a module ‘nstrftime’ that provides an nstrftime function with various GNU extensions.