Although functional but I get string formatting warning during compilation

[anuragvohraec]

Hi,

I am able to compile WITH_LIBUV=1 make, integerate and run uweksockets. However while compiling I get following warnings:

In file included from ../include/uWebSockets/Loop.h:23,
                 from ../include/uWebSockets/HttpContext.h:23,
                 from ../include/uWebSockets/App.h:52,
                 from ../src/server/server.cpp:1:
../include/uWebSockets/LoopData.h: In static member function ‘static void uWS::Loop::create(void*)::<lambda(us_timer_t*)>::_FUN(us_timer_t*)’:
../include/uWebSockets/LoopData.h:78:62: warning: ‘ GMT’ directive output may be truncated writing 4 bytes into a region of size between 0 and 16 [-Wformat-truncation=]
   78 |         snprintf(date, 32, "%.3s, %.2d %.3s %d %.2d:%.2d:%.2d GMT",
      |                                                              ^~~~
In file included from /usr/include/stdio.h:867,
                 from /usr/include/c++/9/cstdio:42,
                 from /usr/include/c++/9/ext/string_conversions.h:43,
                 from /usr/include/c++/9/bits/basic_string.h:6496,
                 from /usr/include/c++/9/string:55,
                 from ../include/uWebSockets/App.h:21,
                 from ../src/server/server.cpp:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:67:35: note: ‘__builtin___snprintf_chk’ output between 21 and 73 bytes into a destination of size 32
   67 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   68 |        __bos (__s), __fmt, __va_arg_pack ());
      |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ../include/uWebSockets/Loop.h:23,
                 from ../include/uWebSockets/HttpContext.h:23,
                 from ../include/uWebSockets/App.h:52,
                 from ../src/server/server.cpp:1:
../include/uWebSockets/LoopData.h: In destructor ‘uWS::TemplatedApp<SSL>::~TemplatedApp() [with bool SSL = true]’:
../include/uWebSockets/LoopData.h:78:62: warning: ‘ GMT’ directive output may be truncated writing 4 bytes into a region of size between 0 and 16 [-Wformat-truncation=]
   78 |         snprintf(date, 32, "%.3s, %.2d %.3s %d %.2d:%.2d:%.2d GMT",
      |                                                              ^~~~
In file included from /usr/include/stdio.h:867,
                 from /usr/include/c++/9/cstdio:42,
                 from /usr/include/c++/9/ext/string_conversions.h:43,
                 from /usr/include/c++/9/bits/basic_string.h:6496,
                 from /usr/include/c++/9/string:55,
                 from ../include/uWebSockets/App.h:21,
                 from ../src/server/server.cpp:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:67:35: note: ‘__builtin___snprintf_chk’ output between 21 and 73 bytes into a destination of size 32
   67 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   68 |        __bos (__s), __fmt, __va_arg_pack ());
      |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ../include/uWebSockets/Loop.h:23,
                 from ../include/uWebSockets/HttpContext.h:23,
                 from ../include/uWebSockets/App.h:52,
                 from ../src/server/server.cpp:1:
../include/uWebSockets/LoopData.h:78:62: warning: ‘ GMT’ directive output may be truncated writing 4 bytes into a region of size between 0 and 16 [-Wformat-truncation=]
   78 |         snprintf(date, 32, "%.3s, %.2d %.3s %d %.2d:%.2d:%.2d GMT",
      |                                                              ^~~~
In file included from /usr/include/stdio.h:867,
                 from /usr/include/c++/9/cstdio:42,
                 from /usr/include/c++/9/ext/string_conversions.h:43,
                 from /usr/include/c++/9/bits/basic_string.h:6496,
                 from /usr/include/c++/9/string:55,
                 from ../include/uWebSockets/App.h:21,
                 from ../src/server/server.cpp:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:67:35: note: ‘__builtin___snprintf_chk’ output between 21 and 73 bytes into a destination of size 32
   67 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   68 |        __bos (__s), __fmt, __va_arg_pack ());
      |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ../include/uWebSockets/Loop.h:23,
                 from ../include/uWebSockets/HttpContext.h:23,
                 from ../include/uWebSockets/App.h:52,
                 from ../src/server/server.cpp:1:
../include/uWebSockets/LoopData.h: In function ‘int setup_server()’:
../include/uWebSockets/LoopData.h:78:62: warning: ‘ GMT’ directive output may be truncated writing 4 bytes into a region of size between 0 and 16 [-Wformat-truncation=]
   78 |         snprintf(date, 32, "%.3s, %.2d %.3s %d %.2d:%.2d:%.2d GMT",
      |                                                              ^~~~
In file included from /usr/include/stdio.h:867,
                 from /usr/include/c++/9/cstdio:42,
                 from /usr/include/c++/9/ext/string_conversions.h:43,
                 from /usr/include/c++/9/bits/basic_string.h:6496,
                 from /usr/include/c++/9/string:55,
                 from ../include/uWebSockets/App.h:21,
                 from ../src/server/server.cpp:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:67:35: note: ‘__builtin___snprintf_chk’ output between 21 and 73 bytes into a destination of size 32
   67 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   68 |        __bos (__s), __fmt, __va_arg_pack ());
      |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ../include/uWebSockets/Loop.h:23,
                 from ../include/uWebSockets/HttpContext.h:23,
                 from ../include/uWebSockets/App.h:52,
                 from ../src/server/server.cpp:1:
../include/uWebSockets/LoopData.h:78:62: warning: ‘ GMT’ directive output may be truncated writing 4 bytes into a region of size between 0 and 16 [-Wformat-truncation=]
   78 |         snprintf(date, 32, "%.3s, %.2d %.3s %d %.2d:%.2d:%.2d GMT",
      |                                                              ^~~~
In file included from /usr/include/stdio.h:867,
                 from /usr/include/c++/9/cstdio:42,
                 from /usr/include/c++/9/ext/string_conversions.h:43,
                 from /usr/include/c++/9/bits/basic_string.h:6496,
                 from /usr/include/c++/9/string:55,
                 from ../include/uWebSockets/App.h:21,
                 from ../src/server/server.cpp:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:67:35: note: ‘__builtin___snprintf_chk’ output between 21 and 73 bytes into a destination of size 32
   67 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   68 |        __bos (__s), __fmt, __va_arg_pack ());
      |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Is there any flag or wrong compilation I did, and how to avoid this warning.

[anuragvohraec]

Ok this is something compiler does.
To swithc this off one can use this flag : -Wno-format-truncation