【C语言】可变参数存储到buffer再做标准输出

#include 
#include 
#include 

char *valist_to_buf(const char *format, ...)
{
    char *p;
    va_list ap;

    if ((p = malloc(4096)) == NULL)
    {
        return (NULL);
    }

    va_start(ap, format);
    (void)vsnprintf(p, 128, format, ap);
    va_end(ap);

    return (p);
}

int main()
{
    char *buf = valist_to_buf("=%=%%=%d=%x=%ld=%f=%c=%sn", 1, 10, 999999999999999, 0.9f, 'c', "abc");
    printf("%s", buf);
    puts(buf);
    free(buf);

    return 0;
}