CODEWITHSUNDEEP
c++g++autotoolsautoconf
Fadecomic
Fadecomic

Reputation: 1268

Autoscan autoconf generated configure script can't find cmath functions in c++ code

I'm confused why a configure script generated by autoscan and autoconf tells me it can't find the functions pow and sqrt in a c++ code that includes the cmath header file. I am calling AC_CHECK_FUNCS([pow sqrt]) (which returns a "no" answer). The code compiles and runs just fine, no errors whatsoever.

C++ code:

#include <cmath>
...
x = sqrt(y);

configure.ac:

AC_CHECK_FUNCS([pow sqrt])

There are no library checks, but I don't need to link -lm on the command line for cmath. I'm not sure if this is the holdup. Seems fairly simple, so I'm confused why it's not working. FYI, g++ 4.1.2, autoconf 2.59, RedHat EL 5.3.

Upvotes: 2

Views: 757

Answers (1)

Benjamin Bannier
Benjamin Bannier

Reputation: 58794

Since you are compiling C++ code you should switch autoconf to run its tests with C++, e.g. add

AC_LANG(C++)

before your checks. This will run the tests with C++, but still only check existence of the corresponding C function. See caveats here.

Upvotes: 3

Related Questions