Version:
m4 version 1.4, all operating systems
Problem description:
The format macro returns a wrong output if you specif an integer number that
terminates with a 0, example try to output the number 10 using:
> format(%f, 10)
1000000
The problem is a bug in the formatting routine format.c:
The following loop is in charge to place the decimal point at the proper location, the
pointer *s is initialized to the string returned by fcvs() whereas trailing zeros are
pruned by clr0(). So for the number 10, s points to the string "1" and decptr is 3, so
the while loop will simply return the string "1" instead of "10.".
while (--decpt >= 0)
*s++ = *t++;
if (n > 0 || alternate)
*s++ = '.';
Solution:
The patch that solves the problem:
453c453
< while (--decpt >= 0)
---
> while (*t && --decpt >= 0)
454a455,456
> while (--decpt>=0)
> *s++ = '0';
And here we go, the proper result for printing the number 10 is:
> format(%f,10)
10.000000
One thing I don't understand is why the format command has an own implementation,
wouldn't it be better to simply use vsprintf() instead ?
My guess is that vsprintf() is not implemented or not consistent on all operating
systems ?
Regards,
Roderick Koehle
---
Roderick Koehle
Infineon Technologies AG, C LITHO TD
Balanstr. 73
81541 Muenchen
Tel: ++49 (89) 234 20746
Fax: ++49 (89) 234 714269
mailto:[EMAIL PROTECTED]
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