| T O P I C R E V I E W |
| lilo |
Posted - 12/05/2002 : 09:37:31 AM
How can I pass a pointer to a function to another function
Here's some code from numerical recipesvoid mrqcof([..other args..], void (*funcs)(float, float, float [], float *, float [], int)){
[..]
(*funcs)(x[i],dfx[dfi],a,&ymod,dyda,ma);
[..]
}
This works fine with gcc but produces the following Compiler error message in Origin:
Error, illegal function argument type
for the 1st line cited here. Does anyone know a fix?
Edited by - lilo on 12/05/2002 09:38:32 AM
Edited by - lilo on 12/05/2002 09:39:56 AM |
| 8 L A T E S T R E P L I E S (Newest First) |
| ML |
Posted - 12/09/2002 : 6:05:48 PM
The void return crash issue will be taken care of in the upcoming service release.
|
| easwar |
Posted - 12/09/2002 : 2:24:48 PM
Hi Dave,
Thank you for reporting this bug. It has been trackred to be fixed in a future service release.
Easwar
OriginLab. |
| Barb Tobias |
Posted - 12/09/2002 : 1:49:26 PM
Hi Dave,
There were quite a few Origin C improvements in SR2. Check out the release notes.
-Barb
|
| dlw21 |
Posted - 12/09/2002 : 12:16:19 PM
Easwar,
This is very interesting. I have 7SR2, but was unaware that this feature had been added.
I was able to get your example to compile and run just fine, but when I tried my own test case, I had a problem. Apparently the OriginC compiler does not like "void" return types for function pointers. If I uncomment the #define as instructed below in my example, the Origin session crashes.
Dave
//------------------------------------------------------------
#include <origin.h>
// Uncomment to force a crash of OriginC in OriginPro 7SR2 (v7.0383)
// on WinXP
//#define CRASHME
#ifdef CRASHME
#define RETURNTYPE void
#else
#define RETURNTYPE int
#endif
typedef RETURNTYPE (*MYFUNCP)(int *ip);
RETURNTYPE printx(int *ip)
{
printf("inside printx\n");
return 0;
}
void call_func(MYFUNCP fp)
{
int i = 0;
fp(&i);
return;
}
void test_funcp(void)
{
call_func(printx);
return;
}
//-------------------------------------------------------------------
|
| dlw21 |
Posted - 12/09/2002 : 12:16:16 PM
Easwar,
This is very interesting. I have 7SR2, but was unaware that this feature had been added.
I was able to get your example to compile and run just fine, but when I tried my own test case, I had a problem. Apparently the OriginC compiler does not like "void" return types for function pointers. If I uncomment the #define as instructed below in my example, the Origin session crashes.
Dave
//------------------------------------------------------------
#include <origin.h>
// Uncomment to force a crash of OriginC in OriginPro 7SR2 (v7.0383)
// on WinXP
//#define CRASHME
#ifdef CRASHME
#define RETURNTYPE void
#else
#define RETURNTYPE int
#endif
typedef RETURNTYPE (*MYFUNCP)(int *ip);
RETURNTYPE printx(int *ip)
{
printf("inside printx\n");
return 0;
}
void call_func(MYFUNCP fp)
{
int i = 0;
fp(&i);
return;
}
void test_funcp(void)
{
call_func(printx);
return;
}
//-------------------------------------------------------------------
|
| easwar |
Posted - 12/06/2002 : 1:57:49 PM
Hi Dave,
Support for function pointers was added in 7SR2. You can get the SR2 patch from our downloads area.
Pasted here is a sample code for quick sort that uses function pointers.
Easwar
OriginLab.
//--------------------------------------------------------------------------------------------------------------------
#define size_t unsigned int
static void MySwap( char *a, char *b, size_t width )
{
char tmp;
if ( a != b )
// Do the swap one character at a time to avoid potential alignment
// problems.
while ( width-- ) {
tmp = *a;
*a++ = *b;
*b++ = tmp;
}
}
static int DoubleComp( const void *arg1, const void *arg2 )
{
double *ldLeft, *ldRight;
ldLeft = (double *)arg1;
ldRight = (double *)arg2;
if ( *ldLeft > *ldRight )
return 1;
else if( *ldLeft < *ldRight )
return -1;
return 0;
}
typedef int (*MYFUNPTRTYPE )(const void *elem1, const void *elem2 );
void MyQsort( void *base, size_t num, size_t width, MYFUNPTRTYPE MyComp )
{
LPSTR lpLeft, lpRight, lpMid, lpLast, lpTemp;
out_str("Entering MyQsort...");
if (num < 2 || width == 0)
{
out_str("EXITING MyQsort...");
return; // nothing to do
}
lpLeft = (char *)base;
lpRight = (char *)base + ( num - 1 )*width;
lpMid = (char *)base + num/2*width;
MySwap( lpLeft, lpMid, width);
lpLast = lpLeft;
for ( lpTemp = lpLeft + width; lpTemp <= lpRight; lpTemp += width )
{
if ( MyComp( lpTemp, lpLeft ) < 0 ) // runtime error here
//if ( DoubleComp( lpTemp, lpLeft ) < 0 ) // runtime error here
{
lpLast += width;
MySwap( lpLast, lpTemp, width );
}
}
MySwap( lpLeft, lpLast, width );
MyQsort(lpLeft, ( lpLast - lpLeft )/ width, width, MyComp);
MyQsort(lpLast + width, ( lpRight - lpLast )/ width, width, MyComp);
out_str("EXITING MyQsort...");
}
void test11()
{
double dd[7] = { 1, 7, 11, 4, 5, 3, 6};
MyQsort(dd, 7, sizeof(double), DoubleComp);
for( int i = 0; i < 7; i++ )
printf (" %f, ", dd[i]);
}
//-----------------------------------------------------------------------------------------------------------------------------
Edited by - easwar on 12/06/2002 2:03:46 PM |
| dlw21 |
Posted - 12/06/2002 : 08:31:13 AM
Hello,
While the above typedef appears to compile a-ok, I can't get code that *uses* it to compile.
Unfortunately, the Origin Programming Guide states pretty unambiguously in the section 'Origin C Programmer's Guide:The Origin Language:Supported Basic and Derived Types':
"=> Origin C does not support function pointers"
I hope OriginLab has plans to add this functionality in the future!
Dave
|
| ML |
Posted - 12/05/2002 : 5:01:24 PM
Try to typedef the function pointer like this:
typedef void (*MYFUNCTYPE)(float, float, float [], float *, float [], int);
and use it like this:
void mrqcof([..other args..], MYFUNCTYPE funcs){
[..]
funcs(x[i],dfx[dfi],a,&ymod,dyda,ma);
[..]
}
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