Max 5 API Reference

ext_critical.h

// critical.h -- platform-independent way to define critical regions

#ifndef _CRITICAL_H_
#define _CRITICAL_H_

#ifdef __cplusplus
extern "C" {
#endif

#if C74_PRAGMA_STRUCT_PACKPUSH
    #pragma pack(push, 2)
#elif C74_PRAGMA_STRUCT_PACK
    #pragma pack(2)
#endif

#define CRITICAL_DEFAULT 2000 * kDurationMillisecond

#ifdef WIN_VERSION
typedef LPCRITICAL_SECTION t_critical;
typedef unsigned long t_thread;
#elif TARGET_API_MAC_CARBON
typedef MPCriticalRegionID t_critical;
typedef ThreadID t_thread;
#else
/**
    A Max critical region.
    @ingroup critical
*/
typedef void t_critical;

/**
    A Max thread.
    @ingroup threading
*/
typedef void t_thread;
#endif


/**
    Create a new critical region.
    Normally, you do not need to create your own critical region, because 
    you can use Max’s global critical region. Only use this function (in 
    your object’s instance creation method) if you are certain you are not 
    able to use the global critical region.
    
    @ingroup    critical
    @param  x   A #t_critical struct will be returned to you via this pointer.
*/
void critical_new(t_critical *x);


/**
    Enter a critical region.
    Typically you will want the argument to be zero to enter the global 
    critical region, although you could pass your own critical created with 
    critical_new(). It is important to try to keep the amount of code in 
    the critical region to a minimum.
    Exit the critical region with critical_exit().
        
    @ingroup    critical
    @param  x   A pointer to a #t_critical struct, or zero to uses Max’s global critical region. 
    @see        critical_exit()
*/
void critical_enter(t_critical x);


/**
    Leave a critical region.
    Typically you will want the argument to be zero to exit the global 
    critical region, although, you if you are using your own critical regions 
    you will want to pass the same one that you previously passed to 
    critical_enter().

    @ingroup    critical
    @param  x   A pointer to a #t_critical struct, or zero to uses Max’s global critical region. 
*/
void critical_exit(t_critical x);


/**
    Free a critical region created with critical_new().
    If you created your own critical region, you will need to free it in your object’s free method.
    
    @ingroup    critical
    @param  x   The #t_critical struct that will be freed.
*/
void critical_free(t_critical x);


/** Try to enter a critical region if it is not locked.
    @ingroup    critical
    @param  x   A pointer to a #t_critical struct, or zero to uses Max’s global critical region. 
    @return     returns non-zero if there was a problem entering
    @see        critical_enter()
*/
short critical_tryenter(t_critical x);


#if C74_PRAGMA_STRUCT_PACKPUSH
    #pragma pack(pop)
#elif C74_PRAGMA_STRUCT_PACK
    #pragma pack()
#endif

#ifdef __cplusplus
}
#endif

#endif // _CRITICAL_H_

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