The -Wwrite-strings warning is enabled by default for C++ code, and its benefit in C code is not really so amazing as to justify its use considering how few C source files we have, so specifying it manually is not very useful. From gcc(1): -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 produces a warning. These warnings 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 is just 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.