strcpy_s not working with gcc

问题:

I have a C++11 project, and I added some strcpy_s method calls. This works on windows, but when compiling on gcc, there is an error stating that strcpy_s symbol is not found.

I did add the line

#define __STDC_WANT_LIB_EXT1__ 1

to the code, to no avail.

回答1:

GCC (or rather, glibc) does not support strcpy_s() and friends. For some ideas on where you can find a library which does support them, see here: Are there any free implementations of strcpy_s and/or TR24731-1?

回答2:

strcpy_s and friends are not a part of C++ just yet. It seems that C++17 will have them, but as of now providing them is up to the implementations. It seems glibc doesn't.

In fact, according to the cppreference, __STDC_WANT_LIB_EXT1__ will only work if __STDC_LIB_EXT1__ is defined. On my Arch Linux it isn't.

#ifdef __STDC_LIB_EXT1__
constexpr bool can_have_strcpy_s = true;
#else
constexpr bool can_have_strcpy_s = false;
#endif

You can use strncpy. With some care, it can be safe.