[HELP] dafault math.h

[geniusdo]

Description

How to replace the default math.h. I tried to use libmcs as my default math lib. I have to directly include "libmcs/math.h" to use libmcs math lib. But I want to directly include math.h in libmcs. I tried the method mentioned in #1503. However when I include math.h it still links to the math lib supplied by my toolchain. Any idea to achieve that?

Verification

• I have verified before submitting the report.

[xiaoxiang781216]

you can include math.h directly, build system already setup the search path automatically:
https://github.com/apache/nuttx/blob/master/tools/Config.mk#L760-L775

[geniusdo]

I am using cxx build. It seems cmath still call math lib from my toolchain

[xiaoxiang781216]

which phase(compe v.s. link) do you reference?

[geniusdo]

During compile phase. I want cmath to use math from libmcs. Idk how it auto links to toolchain math.

[xiaoxiang781216]

it's strange, you need:

1. Issue make V=1 to extract the command line
2. Issue the command line with -E and check the preprocessed output file to know why the wrong file get included