1 /* Emulation of getpagesize() for systems that need it. */ 2 3 /* 4 5 @deftypefn Supplemental int getpagesize (void) 6 7 Returns the number of bytes in a page of memory. This is the 8 granularity of many of the system memory management routines. No 9 guarantee is made as to whether or not it is the same as the basic 10 memory management hardware page size. 11 12 @end deftypefn 13 14 BUGS 15 16 Is intended as a reasonable replacement for systems where this 17 is not provided as a system call. The value of 4096 may or may 18 not be correct for the systems where it is returned as the default 19 value. 20 21 */ 22 23 #ifndef VMS 24 25 #include "config.h" 26 27 #include <sys/types.h> 28 #ifdef HAVE_SYS_PARAM_H 29 #include <sys/param.h> 30 #endif 31 32 #undef GNU_OUR_PAGESIZE 33 #if defined (HAVE_SYSCONF) && defined (HAVE_UNISTD_H) 34 #include <unistd.h> 35 #ifdef _SC_PAGESIZE 36 #define GNU_OUR_PAGESIZE sysconf(_SC_PAGESIZE) 37 #endif 38 #endif 39 40 #ifndef GNU_OUR_PAGESIZE 41 # ifdef PAGESIZE 42 # define GNU_OUR_PAGESIZE PAGESIZE 43 # else /* no PAGESIZE */ 44 # ifdef EXEC_PAGESIZE 45 # define GNU_OUR_PAGESIZE EXEC_PAGESIZE 46 # else /* no EXEC_PAGESIZE */ 47 # ifdef NBPG 48 # define GNU_OUR_PAGESIZE (NBPG * CLSIZE) 49 # ifndef CLSIZE 50 # define CLSIZE 1 51 # endif /* CLSIZE */ 52 # else /* no NBPG */ 53 # ifdef NBPC 54 # define GNU_OUR_PAGESIZE NBPC 55 # else /* no NBPC */ 56 # define GNU_OUR_PAGESIZE 4096 /* Just punt and use reasonable value */ 57 # endif /* NBPC */ 58 # endif /* NBPG */ 59 # endif /* EXEC_PAGESIZE */ 60 # endif /* PAGESIZE */ 61 #endif /* GNU_OUR_PAGESIZE */ 62 63 int 64 getpagesize (void) 65 { 66 return (GNU_OUR_PAGESIZE); 67 } 68 69 #else /* VMS */ 70 71 #if 0 /* older distributions of gcc-vms are missing <syidef.h> */ 72 #include <syidef.h> 73 #endif 74 #ifndef SYI$_PAGE_SIZE /* VMS V5.4 and earlier didn't have this yet */ 75 #define SYI$_PAGE_SIZE 4452 76 #endif 77 extern unsigned long lib$getsyi(const unsigned short *,...); 78 79 int getpagesize (void) 80 { 81 long pagsiz = 0L; 82 unsigned short itmcod = SYI$_PAGE_SIZE; 83 84 (void) lib$getsyi (&itmcod, (void *) &pagsiz); 85 if (pagsiz == 0L) 86 pagsiz = 512L; /* VAX default */ 87 return (int) pagsiz; 88 } 89 90 #endif /* VMS */ 91
