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Torello
Joined: 29 Sep 2006
Posts: 120
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| += operator bug on byte returning of sprintf() ? |
 Posted: Wed Oct 07, 2009 9:28 am |
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Hi,
Up and including version 4093 I could use the += operator on the byte number that is returned when calling sprintf() function. Above 4093 this goes totally wrong. Tested 4095/99
Question is -why- and are there other functions with this strange behaviour.... I really hope not
PS. below is a snippet. I use this construction to conditionally build a string. And also to incorporate some of my own much faster int32 formatting functions.
| Code: |
#include <18F4620.h>
#fuses INTRC_IO, NOFCMEN, IESO, PUT
#fuses NOBROWNOUT, NOWDT, NOPBADEN, LPT1OSC
#fuses MCLR, STVREN, NOLVP
#use delay(clock=4000000)
#use RS232(stream=debug, Baud=9600, Bits=8, Xmit=PIN_B6, Rcv=PIN_B7, DISABLE_INTS)
void main() {
int8 iEoB;
char WrBuf[80];
setup_oscillator(OSC_INTRC | OSC_4MHZ);
fprintf(debug, "<Anykey>: Start test program\n");
fgetc(debug);
// not working anymore
iEoB=0;
fprintf(debug, "iEob=%u\n",iEob);
iEob += sprintf(WrBuf+iEoB,"Hi, why is ");
fprintf(debug, "iEob=%u\n",iEob);
iEob += sprintf(WrBuf+iEoB,"this not worning anymore?\n");
fprintf(debug, "iEob=%u\n",iEob);
fprintf(debug, "%s",WrBuf);
// this does work
iEoB=0;
fprintf(debug, "iEob=%u\n",iEob);
iEob = iEob + sprintf(WrBuf+iEoB,"Hi, why isn't ");
fprintf(debug, "iEob=%u\n",iEob);
iEob = iEob + sprintf(WrBuf+iEoB," += working anymore?\n");
fprintf(debug, "iEob=%u\n",iEob);
fprintf(debug, "%s",WrBuf);
while(1);
} |
| Quote: |
Output:
iEob=0
iEob=0
iEob=0
this not worning anymore?
iEob=0
iEob=14
iEob=35
Hi, why isn't += working anymore?
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Any thoughts welcome...
Kind regards,
Edwin. |
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Wayne_
Joined: 10 Oct 2007
Posts: 681
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| Posted: Wed Oct 07, 2009 9:40 am |
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The help in my version of CCS PCH C Compiler, Version 4.011, 26184 07-Oct-09 16:13
Shows that sprintf does not return anything! |
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FvM
Joined: 27 Aug 2008
Posts: 2337
Location: Germany
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| Posted: Wed Oct 07, 2009 10:03 am |
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| Quote: | | Version 4.011, 26184 07-Oct-09 |
Somewhat outdated. The most recent help clarifies
| Quote: | | Returns: Bytes is the number of bytes written to string. |
(According to the C standard)
Because -the compiler was changed, apparently without sufficient testing. You can see, that several instructions are "optimized away" in the newer code.
| Quote: | | are there other functions with this strange behaviour |
You never know. |
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Torello
Joined: 29 Sep 2006
Posts: 120
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| Posted: Fri Oct 16, 2009 2:51 pm |
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CCS has aswered on my bug report that it is indeed a bug. Will be repaired in the next update.
Regards,
Edwin. |
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