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mjm_graco
Joined: 22 Oct 2020
Posts: 4
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 Posted: Tue Oct 27, 2020 10:24 pm |
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Yeah, that original post was all over the place. My apologies.
This combines the concepts of the 2 pieces of code after this one, and gives the compile error.
s_InputBufferWordPtr is a 2D array of words parsed from an input string. | Quote: | *** Error 144 "main.c" Line 24(1,1): No valid assignment made to function pointer 823 from=??0 0 SCR=1241
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| Code: | #include "18f67k22.h"
#use delay(clock=10M)
#use rs232(baud=9600, UART1, ERRORS)
void TestFunc(int argc, char **argv);
typedef void (*_fptr)(int, char **);
typedef struct
{
char cmdString[10];
_fptr function;
}CommandTableEntry;
CommandTableEntry CommandTable[] = {{"?", TestFunc}};
void main(void)
{
int s_InputBufferWordCount;
char *s_InputBufferWordPtr[16];
_fptr temp;
temp = CommandTable[0].function;
(*temp)(s_InputBufferWordCount, s_InputBufferWordPtr);
}
void TestFunc(int argc, char **argv)
{
for (int i = 0; i < argc; ++i)
{
while(*argv[i])
{
printf("%u: %u\r", i, *argv[i]);
++argv[i];
}
}
} |
This compiles and works (although extra code is required to show it works). Shows the callback with a conventional argument: | Code: | #include <18f67k22.h>
#use delay(clock=10M)
#use rs232(baud=9600, UART1, ERRORS)
void TestFunc(int argc);
typedef void (*_fptr)(int);
typedef struct
{
char cmdString[10];
_fptr function;
}CommandTableEntry;
CommandTableEntry CommandTable[] = {{"?", TestFunc}};
void main(void)
{
int s_InputBufferWordCount;
char *s_InputBufferWordPtr[16];
_fptr temp;
temp = CommandTable[0].function;
(*temp)(s_InputBufferWordCount);
while(1);
}
void TestFunc(int argc)
{
printf("%u\r", argc);
} |
This also compiles and works. Shows s_InputBufferWordPtr being passed to a function, but without the callback. | Code: | #include <18f67k22.h>
#use delay(clock=10M)
#use rs232(baud=9600, UART1, ERRORS)
void TestFunc(int argc, char **argv);
void main(void)
{
int s_InputBufferWordCount;
char *s_InputBufferWordPtr[16];
TestFunc(s_InputBufferWordCount, s_InputBufferWordPtr);
while(1);
}
void TestFunc(int argc, char **argv)
{
for (int i = 0; i < argc; ++i)
{
while(*argv[i])
{
printf("%u: %u\r", i, *argv[i]);
++argv[i];
}
}
} |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19249
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| Posted: Wed Oct 28, 2020 6:47 am |
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Generally, CCS is rather restrictive with regards to handling pointer to
pointers and similar constructs. I've found that usually the best way to
avoid problems is to instead hand all values to functions as integers
(in the case of the PIC18, normally int16), and then convert these
values back to the required pointer where used.
So a fiddle like:
| Code: |
#include <18f67k22.h>
#use delay(clock=10M)
#use rs232(baud=9600, UART1, ERRORS)
void TestFunc(int argc, int16 argv);
typedef void (*_fptr)(int, int16);
typedef struct
{
char cmdString[10];
_fptr function;
}CommandTableEntry;
CommandTableEntry CommandTable[] = {{"?", TestFunc}};
char string[] = "Test message";
void main(void)
{
int s_InputBufferWordCount=1;
char *s_InputBufferWordPtr[16];
_fptr temp;
s_inputBufferWordPtr[0]=string;
s_inputBufferWordPtr[1]=(char *)0;
temp = CommandTable[0].function;
(*temp)(s_InputBufferWordCount, (int16)s_InputBufferWordPtr );
while(TRUE);
}
void TestFunc(int argc, int16 temp)
{
char ** argv;
argv=temp;
printf("%u\r", argc);
for (int i = 0; i < argc; ++i)
{
while(*argv[i])
{
printf("%u: %u\r", i, *argv[i]);
++argv[i];
}
}
}
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Ought to work (possibly...). |
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mjm_graco
Joined: 22 Oct 2020
Posts: 4
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| Posted: Wed Oct 28, 2020 7:29 am |
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| That worked. Thanks for the help - 'tis appreciated. |
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