Control: tags -1 + moreinfo
On 03.12.18 16:06, François Trahay wrote:
> Package: gcc-8
> Version: 8.2.0-9
> Severity: normal
>
> Dear Maintainer,
> I have a piece of code in a CMake project that fails to compile when building
> in RelWithDebInfo mode.
> The problem seems to come from gcc-8 when both -Wall and -O2 options are set:
>
> char* copy_string(const char* str) {
> int len = strlen(str)+1;
> char* dest = malloc(sizeof(char)*len);
> if(dest) {
> strncpy(dest, str, len);
> }
> return dest;
> }
>
> gcc reports the following error:
>
> test_strncpy.c:7:3: error: ‘strncpy’ specified bound depends on the length of
> the source argument [-Werror=stringop-overflow=]
> strncpy(dest, str, len);
> ^~~~~~~~~~~~~~~~~~~~~~~
> test_strncpy.c:5:13: note: length computed here
> int len = strlen(str)+1;
> ^~~~~~~~~~~
> cc1: all warnings being treated as errors
>
>
> In this case, there is no problem in the source code, but -Werror=stringop-
> overflow still reports an error.
>
> Gcc only reports an error when -O2 and -Werror=stringop-overflow (which is
> enabled by -Wall) are set. Replacing strncpy with memcpy also fixes the
> problem.
No, -Werror* is never turned on by -Wall. Please provide a self-contained
example and the command line options used to show the warning/error.
