我正在运行这个示例程序，并且我应该能够从输出中判断它是什么机器类型。我确定它来自检查一两个值，但我应该如何执行此检查？
/* pointers.c - Test pointers
* Written 2012 by F Lundevall
* Copyright abandoned. This file is in the public domain.
*
* To make this program work on as many systems as possible,
* addresses are converted to unsigned long when printed.
* The 'l' in formatting-codes %ld and %lx means a long operand. */
#include <stdio.h>
#include <stdlib.h>
int * ip; /* Declare a pointer to int, a.k.a. int pointer. */
char * cp; /* Pointer to char, a.k.a. char pointer. */
/* Declare fp as a pointer to function, where that function
* has one parameter of type int and returns an int.
* Use cdecl to get the syntax right, http://cdecl.org/ */
int ( *fp )( int );
int val1 = 111111;
int val2 = 222222;
int ia[ 17 ]; /* Declare an array of 17 ints, numbered 0 through 16. */
char ca[ 17 ]; /* Declare an array of 17 chars. */
int fun( int parm )
{
printf( "Function fun called with parameter %d\n", parm );
return( parm + 1 );
}
/* Main function. */
int main()
{
printf( "Message PT.01 from pointers.c: Hello, pointy World!\n" );
/* Do some assignments. */
ip = &val1;
cp = &val2; /* The compiler should warn you about this. */
fp = fun;
ia[ 0 ] = 11; /* First element. */
ia[ 1 ] = 17;
ia[ 2 ] = 3;
ia[ 16 ] = 58; /* Last element. */
ca[ 0 ] = 11; /* First element. */
ca[ 1 ] = 17;
ca[ 2 ] = 3;
ca[ 16 ] = 58; /* Last element. */
printf( "PT.02: val1: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &val1, val1, val1 );
printf( "PT.03: val2: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &val2, val2, val2 );
printf( "PT.04: ip: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &ip, (long) ip, (long) ip );
printf( "PT.05: Dereference pointer ip and we find: %d \n", *ip );
printf( "PT.06: cp: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &cp, (long) cp, (long) cp );
printf( "PT.07: Dereference pointer cp and we find: %d \n", *cp );
*ip = 1234;
printf( "\nPT.08: Executed *ip = 1234; \n" );
printf( "PT.09: val1: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &val1, val1, val1 );
printf( "PT.10: ip: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &ip, (long) ip, (long) ip );
printf( "PT.11: Dereference pointer ip and we find: %d \n", *ip );
printf( "PT.12: val1: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &val1, val1, val1 );
*cp = 1234; /* The compiler should warn you about this. */
printf( "\nPT.13: Executed *cp = 1234; \n" );
printf( "PT.14: val2: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &val2, val2, val2 );
printf( "PT.15: cp: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &cp, (long) cp, (long) cp );
printf( "PT.16: Dereference pointer cp and we find: %d \n", *cp );
printf( "PT.17: val2: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &val2, val2, val2 );
ip = ia;
printf( "\nPT.18: Executed ip = ia; \n" );
printf( "PT.19: ia[0]: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &ia[0], ia[0], ia[0] );
printf( "PT.20: ia[1]: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &ia[1], ia[1], ia[1] );
printf( "PT.21: ip: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &ip, (long) ip, (long) ip );
printf( "PT.22: Dereference pointer ip and we find: %d \n", *ip );
ip = ip + 1; /* add 1 to pointer */
printf( "\nPT.23: Executed ip = ip + 1; \n" );
printf( "PT.24: ip: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &ip, (long) ip, (long) ip );
printf( "PT.25: Dereference pointer ip and we find: %d \n", *ip );
cp = ca;
printf( "\nPT.26: Executed cp = ca; \n" );
printf( "PT.27: ca[0]: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &ca[0], ca[0], ca[0] );
printf( "PT.28: ca[1]: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &ca[1], ca[1], ca[1] );
printf( "PT.29: cp: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &cp, (long) cp, (long) cp );
printf( "PT.30: Dereference pointer cp and we find: %d \n", *cp );
cp = cp + 1; /* add 1 to pointer */
printf( "\nPT.31: Executed cp = cp + 1; \n" );
printf( "PT.32: cp: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &cp, (long) cp, (long) cp );
printf( "PT.33: Dereference pointer cp and we find: %d \n", *cp );
ip = ca; /* The compiler should warn you about this. */
printf( "\nPT.34: Executed ip = ca; \n" );
printf( "PT.35: ca[0]: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &ca[0], ca[0], ca[0] );
printf( "PT.36: ca[1]: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &ca[1], ca[1], ca[1] );
printf( "PT.37: ip: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &ip, (long) ip, (long) ip );
printf( "PT.38: Dereference pointer ip and we find: %d \n", *ip );
cp = ia; /* The compiler should warn you about this. */
printf( "\nPT.39: Executed cp = ia; \n" );
printf( "PT.40: cp: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &cp, (long) cp, (long) cp );
printf( "PT.41: Dereference pointer cp and we find: %d \n", *cp );
printf( "\nPT.42: fp: stored at %lx (hex); value is %ld (dec), %lx (hex)\n",
(long) &fp, (long) fp, (long) fp );
printf( "PT.43: Dereference fp and see what happens.\n" );
val1 = (*fp)(42);
printf( "PT.44: Executed val1 = (*fp)(42); \n" );
printf( "PT.45: val1: stored at %lx (hex); value is %d (dec), %x (hex)\n",
(long) &val1, val1, val1 );
return( 0 );
}
输出
Message PT.01 from pointers.c: Hello, pointy World!
PT.02: val1: stored at 21e50 (hex); value is 111111 (dec), 1b207 (hex)
PT.03: val2: stored at 21e54 (hex); value is 222222 (dec), 3640e (hex)
PT.04: ip: stored at 21eb8 (hex); value is 138832 (dec), 21e50 (hex)
PT.05: Dereference pointer ip and we find: 111111
PT.06: cp: stored at 21e6c (hex); value is 138836 (dec), 21e54 (hex)
PT.07: Dereference pointer cp and we find: 0
PT.08: Executed *ip = 1234;
PT.09: val1: stored at 21e50 (hex); value is 1234 (dec), 4d2 (hex)
PT.10: ip: stored at 21eb8 (hex); value is 138832 (dec), 21e50 (hex)
PT.11: Dereference pointer ip and we find: 1234
PT.12: val1: stored at 21e50 (hex); value is 1234 (dec), 4d2 (hex)
PT.13: Executed *cp = 1234;
PT.14: val2: stored at 21e54 (hex); value is -771529714 (dec), d203640e (hex)
PT.15: cp: stored at 21e6c (hex); value is 138836 (dec), 21e54 (hex)
PT.16: Dereference pointer cp and we find: -46
PT.17: val2: stored at 21e54 (hex); value is -771529714 (dec), d203640e (hex)
PT.18: Executed ip = ia;
PT.19: ia[0]: stored at 21e74 (hex); value is 11 (dec), b (hex)
PT.20: ia[1]: stored at 21e78 (hex); value is 17 (dec), 11 (hex)
PT.21: ip: stored at 21eb8 (hex); value is 138868 (dec), 21e74 (hex)
PT.22: Dereference pointer ip and we find: 11
PT.23: Executed ip = ip + 1;
PT.24: ip: stored at 21eb8 (hex); value is 138872 (dec), 21e78 (hex)
PT.25: Dereference pointer ip and we find: 17
PT.26: Executed cp = ca;
PT.27: ca[0]: stored at 21e58 (hex); value is 11 (dec), b (hex)
PT.28: ca[1]: stored at 21e59 (hex); value is 17 (dec), 11 (hex)
PT.29: cp: stored at 21e6c (hex); value is 138840 (dec), 21e58 (hex)
PT.30: Dereference pointer cp and we find: 11
PT.31: Executed cp = cp + 1;
PT.32: cp: stored at 21e6c (hex); value is 138841 (dec), 21e59 (hex)
PT.33: Dereference pointer cp and we find: 17
PT.34: Executed ip = ca;
PT.35: ca[0]: stored at 21e58 (hex); value is 11 (dec), b (hex)
PT.36: ca[1]: stored at 21e59 (hex); value is 17 (dec), 11 (hex)
PT.37: ip: stored at 21eb8 (hex); value is 138840 (dec), 21e58 (hex)
PT.38: Dereference pointer ip and we find: 185664256
PT.39: Executed cp = ia;
PT.40: cp: stored at 21e6c (hex); value is 138868 (dec), 21e74 (hex)
PT.41: Dereference pointer cp and we find: 0
PT.42: fp: stored at 21e70 (hex); value is 69288 (dec), 10ea8 (hex)
PT.43: Dereference fp and see what happens.
Function fun called with parameter 42
PT.44: Executed val1 = (*fp)(42);
PT.45: val1: stored at 21e50 (hex); value is 43 (dec), 2b (hex)