https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70311
Bug ID: 70311
Summary: libgfortran build dies on "implicit declaration of
function strncasecmp"
Product: gcc
Version: 5.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libfortran
Assignee: unassigned at gcc dot gnu.org
Reporter: keith.marshall at mailinator dot com
Target Milestone: ---
I've just succeeded in building GCC-5.3.0 as a GNU/Linux hosted cross-compiler
for the mingw32 target. However, I did need to add:
#include <strings.h>
to each of the following libgfortran source files:
libgfortran/intrinsics/selected_char_kind.c
libgfortran/runtime/environ.c
libgfortran/runtime/string.c
This is required, because the prototype for the POSIX.1 strncasecmp() function
is correctly declared in <strings.h>, which these three libgfortran sources do
not include; (they do include <string.h>, but that's a distinct header, with a
different, ISO-C conforming purpose; in a strictly conforming POSIX.1 context,
it does not declare strncasecmp(), and recent changes to the MinGW.org runtime
headers have introduced this conformity requirement).
In addition, I ran into an issue surrounding the implementation of the
strnlen() function ... again an implicit declaration issue. For the mingw32
target, this issue is less clearly defined: the function is available on hosts
from Windows-Vista onwards, (and the GCC configure script may detect it), but
the prototype is not exposed in the headers for a default mingw32 build, (since
the default aims to support earlier Windows versions). My work-around was:
-#ifndef HAVE_STRNLEN
+#if ! defined HAVE_STRNLEN || (defined _WIN32 && ! defined __CYGWIN__)
so selecting the local replacement function in libgfortran/runtime/string.c;
this may be a prudent configuration choice for _WIN32 in any case, since the
build-time detection of strnlen(), may become invalid at run-time.
