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/* Emulation of getpagesize() for systems that need it. */

/*

@deftypefn Supplemental int getpagesize (void)

Returns the number of bytes in a page of memory.  This is the

granularity of many of the system memory management routines.  No

guarantee is made as to whether or not it is the same as the basic

memory management hardware page size.

@end deftypefn

BUGS

        Is intended as a reasonable replacement for systems where this

        is not provided as a system call.  The value of 4096 may or may

        not be correct for the systems where it is returned as the default

        value.

*/

#ifndef VMS

#include "config.h"

#include <sys/types.h>

#ifdef HAVE_SYS_PARAM_H

#include <sys/param.h>

#endif

#undef GNU_OUR_PAGESIZE

#if defined (HAVE_SYSCONF) && defined (HAVE_UNISTD_H)

#include <unistd.h>

#ifdef _SC_PAGESIZE

#define GNU_OUR_PAGESIZE sysconf(_SC_PAGESIZE)

#endif

#endif

#ifndef GNU_OUR_PAGESIZE

# ifdef PAGESIZE

#  define       GNU_OUR_PAGESIZE PAGESIZE

# else  /* no PAGESIZE */

#  ifdef        EXEC_PAGESIZE

#   define      GNU_OUR_PAGESIZE EXEC_PAGESIZE

#  else /* no EXEC_PAGESIZE */

#   ifdef       NBPG

#    define     GNU_OUR_PAGESIZE (NBPG * CLSIZE)

#    ifndef     CLSIZE

#     define    CLSIZE 1

#    endif      /* CLSIZE */

#   else        /* no NBPG */

#    ifdef      NBPC

#     define    GNU_OUR_PAGESIZE NBPC

#    else       /* no NBPC */

#     define    GNU_OUR_PAGESIZE 4096   /* Just punt and use reasonable value */

#    endif /* NBPC */

#   endif /* NBPG */

#  endif /* EXEC_PAGESIZE */

# endif /* PAGESIZE */

#endif /* GNU_OUR_PAGESIZE */

int

getpagesize (void)

{

  return (GNU_OUR_PAGESIZE);

}

#else /* VMS */

#if 0   /* older distributions of gcc-vms are missing <syidef.h> */

#include <syidef.h>

#endif

#ifndef SYI$_PAGE_SIZE  /* VMS V5.4 and earlier didn't have this yet */

#define SYI$_PAGE_SIZE 4452

#endif

extern unsigned long lib$getsyi(const unsigned short *,...);

int getpagesize (void)

{

  long pagsiz = 0L;

  unsigned short itmcod = SYI$_PAGE_SIZE;

  (void) lib$getsyi (&itmcod, (void *) &pagsiz);

  if (pagsiz == 0L)

    pagsiz = 512L;      /* VAX default */

  return (int) pagsiz;

}

#endif /* VMS */