src/ec_filter.c:516:14: error: call to undeclared function 'memmem'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]

[asarubbo]

Hi,

clang-16 forces -Wimplicit-function-declaration so ettercap fails to compile.

To reproduce you can use clang16 or force -Werror=implicit-function-declaration with previous version of clang and/or gcc

Downstream report from tinderbox is here: https://bugs.gentoo.org/897820

[koeppea]

I've compiled latest source with CLang version 13 on a FreeBSD machine with the compiler flag -Werror=implicit-function-declaration explicitly set.

With that I don't get any build error or warning.

[LocutusOfBorg]

@asarubbo also latest git? because ec_filter.c includes ec.h and it has "#include "

[LocutusOfBorg]

I tried clang-16 from Debian experimental, no implicit-function-declaration, with both latest stable and this master branch

[asarubbo]

Did you try if it fails with the combo of musl+clang 16 as reported in the downstream bug ?

[LocutusOfBorg]

Agostino, so looks more a musl bug then?

[LocutusOfBorg]

grep memmem /usr/include/ -R /usr/include/x86_64-linux-musl/string.h:void memmem(const void , size_t, const void , size_t); /usr/include/string.h:extern void memmem (const void *__haystack, size_t __haystacklen,

I see it being defined, but maybe nobody is including string.h (musl) but instead the string.h

#ifdef _GNU_SOURCE 
#define strdupa(x)      strcpy(alloca(strlen(x)+1),x)
int strverscmp (const char *, const char *);
char *strchrnul(const char *, int);
char *strcasestr(const char *, const char *);
void *memmem(const void *, size_t, const void *, size_t);
void *memrchr(const void *, int, size_t);
void *mempcpy(void *, const void *, size_t); 
#ifndef __cplusplus
char *basename();
#endif
#endif

This is how musl is defining it, I don't see any issue

[thesamesam]

musl doesn't automatically define _GNU_SOURCE and only exposes memmem if _GNU_SOURCE is set.

CMake doesn't have a nice magic way to enable _GNU_SOURCE like autotools does (autotools has AC_USE_SYSTEM_EXTENSIONS), see https://gitlab.kitware.com/cmake/cmake/-/issues/21226, but you can do:

set(CMAKE_C_STANDARD 99)
set(CMAKE_C_STANDARD_REQUIRED ON)
set(CMAKE_C_EXTENSIONS ON)
string(APPEND CMAKE_C_FLAGS "-D_GNU_SOURCE") # needed for memmem

... or similar. Let me know if you need me to poke at it more.

[LocutusOfBorg]

@asarubbo can you please check if https://github.com/Ettercap/ettercap/pull/1220 fixes the issue?

[koeppea]

Merged #1220 which fixes this issue. Thanks