On 26/05/2023 18:34, Bruno Haible wrote:
In GNU gettext, I see these compilation warnings with gcc 13.1.0:gcc ... -Wall -Wno-cast-qual -Wno-conversion -Wno-float-equal -Wno-sign-compare -Wno-undef -Wno-unused-function -Wno-unused-parameter -Wno-float-conversion -Wimplicit-fallthrough -Wno-pedantic -Wno-sign-conversion -Wno-type-limits -Wno-unsuffixed-float-constants -g -O2 -c copy-file.c -fPIC -DPIC -o .libs/libgettextlib_la-copy-file.o copy-file.c: In function 'copy_file_preserving': copy-file.c:192:7: warning: this statement may fall through [-Wimplicit-fallthrough=] 192 | error (EXIT_FAILURE, errno, _("error while opening %s for reading"), | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 193 | quote (src_filename)); | ~~~~~~~~~~~~~~~~~~~~~ copy-file.c:195:5: note: here 195 | case GL_COPY_ERR_OPEN_BACKUP_WRITE: | ^~~~ and so on. The option -Wimplicit-fallthrough gets added as part of GL_CFLAG_GNULIB_WARNINGS (collected by gl_CC_GNULIB_WARNINGS in m4/gnulib-common.m4). That explains why I'm not seeing these warnings in gnulib testdirs. It's probably too hard to teach gcc that error (EXIT_FAILURE, ...) does not return but error (0, ...) does return. Therefore just disabling this warning seems the best action.
FWIW grep/coreutils use a die() wrapper to achieve this for this common idiom. https://github.com/coreutils/coreutils/commit/dad7ab0b7 cheers, Pádraig.
