If you are on windows and using mingw, gcc uses the win32 runtime, where printf needs %I64d
for a 64 bit integer. (and %I64u
for an unsinged 64 bit integer)
For most other platforms you'd use %lld
for printing a long long. (and %llu
if it's unsigned). This is standarized in C99.
gcc doesn't come with a full C runtime, it defers to the platform it's running on - so the general case is that you need to consult the documentation for your particular platform - independent of gcc.