No compiler warning for obvious segfault

Question

I am surprised this compiles without any warning:

int main()
{ 
    *"abc" = '\0';
}

with gcc main.c -Wall -Wextra and clang main.c -Weverything.

Why is there no warning for this ? Is there any way this could not raise a segmentation fault ?

Answer 1

You can use -Wwrite-strings to get a warning for this code in GCC. From the GCC documentation:

-Wwrite-strings

When compiling C, give string constants the type const char[length] so that copying the address of one into a non-const char * pointer will get a warning. These warnings will help you find at compile time code that can try to write into a string constant, but only if you have been very careful about using const in declarations and prototypes. Otherwise, it will just be a nuisance. This is why we did not make -Wall request these warnings.

When compiling C++, warn about the deprecated conversion from string literals to char *. This warning is enabled by default for C++ programs.

"Is there any way this could not raise a segmentation fault ?" -> It is undefined behavior to modify a string litteral. So anything could happen, including not segfaulting.