On 10/13/2010 05:06 PM, wilbur.chan wrote:
I am planning to use va_list on a single module, however the
following code did not work properly.
typedef char * va_list;
#define _INTSIZEOF(n) ( (sizeof(n) + sizeof(int) - 1)& ~(sizeof(int) - 1) )
#define va_start(ap,v) ( ap = (va_list)&v + _INTSIZEOF(v) )
#define va_arg(ap,t) ( *(t *)((ap += _INTSIZEOF(t)) - _INTSIZEOF(t)) )
#define va_end(ap) ( ap = (va_list)0 )
You cannot arbitrarily define those macros with garbage and expect
anything to work.
Replace all the above code with #include <stdarg.h>
Then do: man stdarg
That documents how it works.
David Daney
void test_val_list()
{
unsigned long test=0x1234;
test_printk("test:0x%x OK\n",aaa);
}
void test_printk(const char *format, ...)
{
va_list args;
va_start(args, format);
unsigned int v1 = va_arg(args,unsigned long);
printk("v1 is 0x%x\n",v1);
unsigned int v2 = va_arg(args,unsigned long);
printk("v2 is 0x%x\n",v2);
}
The result is :
v1 is 0x00000013
v2 is 0x00000019
Why this happened ? shouldn't v1 be 0x1234 here?
Thank you
