c语言实现调度器

c语言实现调度器

原文：https://gist.github.com/hlippek/3187590

https://www.cs.ucr.edu/~vahid/rios/

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#include <stdio.h> #include <string.h> #include <stdlib.h>   #define MAX_PROCESSES 32  /* the maximal number of processes in the system */ #define MAX_NAME_LEN  32   /* Process control block -  * holding all process relevant informations */ struct pcb{     int pid;                   /* ID of the proces */     int prio;                  /* process priority */     int attached;              /* 1 if attached to processlist, else 0 */     int *function;             /* pointer to the process function */     char name[MAX_NAME_LEN];   /* Name of the process */ };   static struct pcb processlist[MAX_PROCESSES]; int process0(); int process1();   int process_attach(char *name, int prio, void *function) {     int i = 0;     int ret = -1;     printf("[dbg] process_attach\n");     while(i < MAX_PROCESSES)     {         if(strlen(name) > MAX_NAME_LEN)         {             printf("[err] wrong stringlen\n");             return ret;         }                       if(processlist[i].attached != 1)         {             printf("attach process at %d\n", i);             processlist[i].pid = i;             strcpy(processlist[i].name, name);             processlist[i].prio = prio;             processlist[i].function = function;             processlist[i].attached = 1;             ret = 0;             break;         }         printf("\n");         i++;     }     return ret;         }   int process_detach(int pid) {     processlist[pid].attached = 0;     return 0; }   /*  * basic implementation of a RR scheduler  */ int scheduler() {     int i = 0;     void (*p)(void);           while(1)     {         for(i = 0; i < MAX_PROCESSES; i++)         {             if(processlist[i].attached == 1)             {                 p = (void *)processlist[i].function;                 (*p)();             }         }     }     return 0; }   /*** Testdriver ***/ int process0() {     printf("0\n");     return 0; }   int process1() {     printf("1\n");     return 0; }   int main() {     /*      * test run here      * */     printf("basic_scheduler Demo\n");     process_attach("process0", 100, process0);     process_attach("process1", 50,  process1);     scheduler();     return 0; }