protobuf/ruby/ext/google/protobuf_c/wrap_memcpy.c

// Protocol Buffers - Google's data interchange format
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// https://developers.google.com/protocol-buffers/
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#include <string.h>

// On x86-64 Linux with glibc, we link against the 2.2.5 version of memcpy so
// that we avoid depending on the 2.14 version of the symbol. This way,
// distributions that are using pre-2.14 versions of glibc can successfully use
// the gem we distribute (https://github.com/protocolbuffers/protobuf/issues/2783).
//
// This wrapper is enabled by passing the linker flags -Wl,-wrap,memcpy in
// extconf.rb.
#ifdef __linux__
#if defined(__x86_64__) && defined(__GNU_LIBRARY__)
__asm__(".symver memcpy,memcpy@GLIBC_2.2.5");
void *__wrap_memcpy(void *dest, const void *src, size_t n) {
    return memcpy(dest, src, n);
}
#else
void *__wrap_memcpy(void *dest, const void *src, size_t n) {
    return memmove(dest, src, n);
}
#endif
#endif