Digging into printk internals so I truly *understand* what is going on ..

gistfile1.c

printk is defined as a function in:
- arch/ia64/kvm/vmm.c, line 84
- kernel/printk/printk.c, line 1677 // This is what we need for kernel module work
 
1677 asmlinkage __visible int printk(const char *fmt, ...) // char * fmt is a member 
1678 {                                                     // of structure va_format ( shown below )
1679 va_list args;
1680 int r;
1681
1682 #ifdef CONFIG_KGDB_KDB
1683 if (unlikely(kdb_trap_printk)) {
1684 va_start(args, fmt);
1685 r = vkdb_printf(fmt, args);
1686 va_end(args);
1687 return r;
1688 }
1689 #endif
1690 va_start(args, fmt);
1691 r = vprintk_emit(0, -1, NULL, 0, fmt, args);
1692 va_end(args);
1693
1694 return r;
1695 }
1696 EXPORT_SYMBOL(printk); // Symbol is exported so kernel modules can use it

51 struct va_format {
52         const char *fmt; // used by int printk(const char *fmt, ...)
53         va_list *va;
54 }; 
 
line # 132:
int printk(const char *fmt, ...);
 
 
 
line # 167:
int printk(const char *s, ...)
{
return 0;
}
 
va_format
Defined as a struct type in:


Defined as a type in:include/acpi/platform/acenv.h, line 361
 
359 #ifndef _VALIST
360 #define _VALIST
361 typedef char *va_list;
362 #endif /* _VALIST */