3 C macros that allow for multiple "tasks" to execute in parallel:
#define TASK_INIT() static void* f; if(f) goto *f;
#define TASK_YIELD() { __label__ END; f=&&END; return; END: ; }
#define TASK_END() f=0;
// It compiles under gcc. Automatic variables are NOT preserved! One would use it like so:
void testingSub1(){
TASK_INIT();
printf("A");
TASK_YIELD();
printf("B");
TASK_YIELD();
printf("C");
TASK_END();
}
void testingSub2(){
TASK_INIT();
printf("1");
TASK_YIELD();
printf("2");
TASK_YIELD();
printf("3");
TASK_YIELD();
printf("4");
TASK_END();
}
void testingSub3(){
TASK_INIT();
while(1){
printf("*");
TASK_YIELD();
}
TASK_END();
}
void testing(){
testingSub1();
testingSub2();
testingSub3();
printf("|");
}
When testing() is called repeatedly, the output looks like this:
C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|B2*|C3*|A4*|B1*|C2*|A3*|B4*|C1*|A2*|B3*|C4*|A1*|