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#include "apue.h"
#include <errno.h>
#include <limits.h>

#ifdef OPEN_MAX
static long openmax = OPEN_MAX;
#else
static long openmax = 0;
#endif

#define OPEN_MAX_GUESS 256

long open_max(void)
{
	if(openmax == 0){
		errno = 0;
		if((openmax= sysconf(_SC_OPEN_MAX)) < 0){
			if(errno == 0)
				openmax=OPEN_MAX_GUESS;
			else
				err_sys("sysconf error for _SC_OPEN_MAX");
		}
	}

	return openmax;
}

 

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