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#include "gis.h"
#include <unistd.h>
/*******************************************************
*
* G_write_zeros (fd ,n)
* int fd
* long n
*
* writes n bytes of zero to file descriptor fd
******************************************************/
int G_write_zeros(int fd, long n)
{
char zeros[1024];
register char *z;
register int i;
/*
* there is a subtle gotcha to be avoided here
* i must be an int for the write, but n can be long
* must be careful not to cast long to int, hence must
* avoid i = n unless n is within range of int
*/
if (n <= 0)
return 0;
/* fill zeros buffer with zeros */
if (n > sizeof zeros)
i = sizeof zeros;
else
i = n; /* this is ok here */
z = zeros;
while (i--)
*z++ = 0;
/* write n zeros to fd */
while (n > 0)
{
if (n > sizeof zeros)
i = sizeof zeros;
else
i = n; /* this is ok here */
write (fd, zeros, i);
n -= i;
}
return 0;
}
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