Flags are similar to binary semaphores. There are two differences:

1. you can wait, check, set or reset several flags at one time;
2. after accepting flags their values do not change.

The using of flags can be usefull when task requires the results of several tasks. For example to calculate some physical parameters task needs information about the temperature, pressure and humidity. Each of these parameters is measured in it's own task and set flag when measuring is complete.

#include <osa.h>
 
OST_FLAG8   F_Sensors;
 
#define  TEMPERATURE_MEASURED   0x01
#define  PRESSURE_MEASURED      0x02
#define  HUMIDITY_MEASURED      0x04
 
void Task_Calc (void)
{
    for (;;) {
        // Wait for all measurings complete
        OS_Flag_Wait_11(F_Sensors, TEMPERATURE_MEASURED | PRESSURE_MEASURED | HUMIDITY_MEASURED);
        OS_Flag_Set_0(F_Sensors, TEMPERATURE_MEASURED | PRESSURE_MEASURED | HUMIDITY_MEASURED);
 
        // Now we can to calculate
        ...
    }
}

There are three types of flags: 8-, 16- and 32-bit.

OST_FLAG      MyFlag1;	//  8-bit flags
OST_FLAG16    MyFlag2;	// 16-bit flags
OST_FLAG32    MyFlag3;	// 32-bit flags

It is possible to use defferent size of flags at one time.

Flags can be allocated in any memory bank, i.e.:

bank2    OST_FLAG16   MyFlag;