91 lines
2 KiB
C
91 lines
2 KiB
C
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/* Emulation of getpagesize() for systems that need it. */
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/*
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@deftypefn Supplemental int getpagesize (void)
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Returns the number of bytes in a page of memory. This is the
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granularity of many of the system memory management routines. No
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guarantee is made as to whether or not it is the same as the basic
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memory management hardware page size.
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@end deftypefn
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BUGS
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Is intended as a reasonable replacement for systems where this
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is not provided as a system call. The value of 4096 may or may
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not be correct for the systems where it is returned as the default
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value.
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*/
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#ifndef VMS
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#include "config.h"
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#include <sys/types.h>
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#ifdef HAVE_SYS_PARAM_H
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#include <sys/param.h>
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#endif
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#undef GNU_OUR_PAGESIZE
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#if defined (HAVE_SYSCONF) && defined (HAVE_UNISTD_H)
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#include <unistd.h>
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#ifdef _SC_PAGESIZE
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#define GNU_OUR_PAGESIZE sysconf(_SC_PAGESIZE)
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#endif
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#endif
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#ifndef GNU_OUR_PAGESIZE
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# ifdef PAGESIZE
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# define GNU_OUR_PAGESIZE PAGESIZE
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# else /* no PAGESIZE */
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# ifdef EXEC_PAGESIZE
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# define GNU_OUR_PAGESIZE EXEC_PAGESIZE
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# else /* no EXEC_PAGESIZE */
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# ifdef NBPG
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# define GNU_OUR_PAGESIZE (NBPG * CLSIZE)
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# ifndef CLSIZE
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# define CLSIZE 1
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# endif /* CLSIZE */
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# else /* no NBPG */
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# ifdef NBPC
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# define GNU_OUR_PAGESIZE NBPC
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# else /* no NBPC */
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# define GNU_OUR_PAGESIZE 4096 /* Just punt and use reasonable value */
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# endif /* NBPC */
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# endif /* NBPG */
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# endif /* EXEC_PAGESIZE */
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# endif /* PAGESIZE */
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#endif /* GNU_OUR_PAGESIZE */
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int
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getpagesize (void)
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{
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return (GNU_OUR_PAGESIZE);
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}
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#else /* VMS */
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#if 0 /* older distributions of gcc-vms are missing <syidef.h> */
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#include <syidef.h>
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#endif
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#ifndef SYI$_PAGE_SIZE /* VMS V5.4 and earlier didn't have this yet */
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#define SYI$_PAGE_SIZE 4452
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#endif
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extern unsigned long lib$getsyi(const unsigned short *,...);
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int getpagesize (void)
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{
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long pagsiz = 0L;
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unsigned short itmcod = SYI$_PAGE_SIZE;
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(void) lib$getsyi (&itmcod, (void *) &pagsiz);
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if (pagsiz == 0L)
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pagsiz = 512L; /* VAX default */
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return (int) pagsiz;
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}
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#endif /* VMS */
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