sys/src/libc/port/atnotify.c

   1 #include <u.h>
   2 #include <libc.h>
   3
   4 #define NFN     33
   5 static  int     (*onnot[NFN])(void*, char*);
   6 static  Lock    onnotlock;
   7
   8 static
   9 void
  10 notifier(void *v, char *s)
  11 {
  12         int i;
  13
  14         for(i=0; i<NFN; i++)
  15                 if(onnot[i] && ((*onnot[i])(v, s))){
  16                         noted(NCONT);
  17                         return;
  18                 }
  19         noted(NDFLT);
  20 }
  21
  22 int
  23 atnotify(int (*f)(void*, char*), int in)
  24 {
  25         int i, n, ret;
  26         static int init;
  27
  28         if(!init){
  29                 notify(notifier);
  30                 init = 1;               /* assign = */
  31         }
  32         ret = 0;
  33         lock(&onnotlock);
  34         if(in){
  35                 for(i=0; i<NFN; i++)
  36                         if(onnot[i] == 0) {
  37                                 onnot[i] = f;
  38                                 ret = 1;
  39                                 break;
  40                         }
  41         }else{
  42                 n = 0;
  43                 for(i=0; i<NFN; i++)
  44                         if(onnot[i]){
  45                                 if(ret==0 && onnot[i]==f){
  46                                         onnot[i] = 0;
  47                                         ret = 1;
  48                                 }else
  49                                         n++;
  50                         }
  51                 if(n == 0){
  52                         init = 0;
  53                         notify(0);
  54                 }
  55         }
  56         unlock(&onnotlock);
  57         return ret;
  58 }