C++ 安全字符串拼接

#include <stdio.h>
#include <stdint.h>
#include <stdarg.h>

#if defined(__GNUC__)
#endif

#if defined(_MSC_VER)
#define snprintf(buf,size,fmt,...) sprintf_s(buf,size,fmt,__VA_ARGS__)
#define vsnprintf(buf,size,fmt,...) vsprintf_s(buf,size,fmt,__VA_ARGS__)
#endif

#define STRAPPEND(buf, size, offset, fmt, ...) do { 
if (offset < size) 
    { 
    offset += snprintf(buf + offset, size - offset, fmt, __VA_ARGS__); 
    }
}while (0)


inline void StrAppend(char buf[], const uint32_t bufLen, uint32_t &offset, const char *fmt, ...)
{
    va_list argptr;
    va_start(argptr, fmt);
    if (offset < bufLen)
    {
        offset += vsnprintf(buf + offset, bufLen - offset, fmt, argptr);
    }
    va_end(argptr);
}

int32_t main(int32_t argc, char *argv[])
{
    char buf[64] = { 0 };
    uint32_t offset = 0;
    StrAppend(buf, 64, offset, "%d ", 12);
    StrAppend(buf, 64, offset, ",%s--", "qwe");
    StrAppend(buf, 64, offset, ",%0.2f!!!", 1.0);
    printf("%s
", buf);
    offset = 0;
    STRAPPEND(buf, 64, offset, "%d ", 121);
    STRAPPEND(buf, 64, offset, ",%s--", "qwe1");
    STRAPPEND(buf, 64, offset, ",%0.3f!!!", 11.0);
    printf("%s
", buf);
    return 0;
}