Documentation comments...

["Brian J. Dent" <briandent at redshift dot com>]

gcc-bugs,

I have a comment on the GNU documentation.  This may be the wrong
venue but if you would forward it to the correct party I would appreciate
it.  

I've been working on compiling a program on our Sun that was working and
then we added a call to sqrt and broke the link.  From there I've
searched the on-line documentation for information about sqrt.  To
say it was sparse would be an understatement.  Finally after a bit
of searching I sent an email (below) which was answered in about 5
minutes with the obvious fix of:  link with -lm.  Duh. 
Once I knew what I was looking for I was able to find a reference:

 From the introduction of a libc.a reference, "Note that many of the
functions in `libm.a' (the math library) are defined
in `math.h' but are not present in
libc.a."  You must link with -lm to link in the math
library.  The URL for this reference is
http://www.delorie.com/djgpp/doc/libc-2.02/.

My comment overall is that I shouldn't have had to dig through so much
documentation without finding what appears now to be an obvious
point.  I can find very explicit information on peep-hole
optimization and other items.  But the mundane information is harder
to come by.  Next update to the documentation you might want to
consider the addition of some type of primer/library
refernence/etc.  Something that helps new users gain traction more
quickly than now.  My 2 cents.

-----------------------------------------------------------------------------------------------------------

gcc help,

Obviously I am new to the GNU gcc compiler. 

I've been trying compile a program on our SUN with gcc
(sparc-sun-solaris2.7/2.95.1) and it contains some intrinsic functions.
When I get to the point of linking it doesn't recognize the functions,
eg: sqrt. Below is a test program. What is missing that I am not finding
the built-in functions to link with? Thanks for any help.

file:marc.c:
#include <stdio.h> 
#include <math.h>
main() 
{ 
double x = 2; 
printf("sqrt of %e is %e\n",x,sqrt(x)); 
}
gcc -c marc.c 
gcc -o marc.out marc.o 
Undefined first referenced 
symbol in file 
sqrt marc.o 
ld: fatal: Symbol referencing errors. No output written to marc.out 
collect2: ld returned 1 exit status

- bjd

____________________________

Brian J. Dent

CompuDent

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http://www.redshift.com/~briandent/