gcc compiler, version egcs 1.1.1

gcc compiler, version egcs 1.1.1

[Henry Abrecht]

Hello,

I have what I believe is version 2.8.1 of your c compiler--or is it
> egcs-1.1.1? I got that number from the man notes on gcc. My platform is Caldera OpenLinux 2.2. 

  My problem: I'm trying to declare and call math
> functions--specifically sin(x), cos(x), sqrt(x), pow(x, y).
> When I call them and include math.h (or is it tgmath.h?) I get
the
> message: "function undefined." When I declare them (ex: double
> sqrt(double)) I get the same message.
> 
> My question: What's the correct prototype format for these
functions?
> (or more generally, how are they declared and called?) If it
helps, I'm
> using a book called "A Book on C," by Al Kelley and Ira Pohl. On
his Web
> site Pohl indicates that libraries used by c compilers might have
changed
> since he wrote his book. He recommends that users contact the compiler maker for the correct function prototypes. (Pohl's book is based on GCC 2.7.)

Thanks,
Henry Abrecht

Re: gcc compiler, version egcs 1.1.1

[Martin v. Loewis]

>   My problem: I'm trying to declare and call math
> functions--specifically sin(x), cos(x), sqrt(x), pow(x, y).  When I
> call them and include math.h (or is it tgmath.h?) I get the message:
> "function undefined." When I declare them (ex: double sqrt(double))
> I get the same message.

I doubt that the message you get literally reads "function
undefined". It is very important that you quote error message
literally as they appear on the terminal.

> My question: What's the correct prototype format for these
> functions? (or more generally, how are they declared and called?)

You should never declare the functions yourself; instead, use the
appropriate header file. For sin/cos/sqrt/pow, the header file is
indeed math.h, so there is no need to declare the functions further.

I believe your problem is not that the functions where not declared,
but that no implementation was found, i.e. that the error message read

undefined reference to `sin'

In that case, you should tell the compiler to link with the math
library, i.e. you need to add -lm.

Regards,
Martin