CODEWITHSUNDEEP
c++makefile
Dianne
Dianne

Reputation: 196

What does the "@" symbol mean in a makefile when after an -I flag such as -I @mathinc@?

I'm trying to understand the following line in a Makefile.in file:

CXXFLAGS += -O3 -DNDEBUG -std=c++11 -Wno-deprecated-declarations -Isrc -I @mathinc@

I know the -I flag adds a directory to the list of places where the compiler will search for included files but what does @mathinc@ mean?

Upvotes: 0

Views: 53

Answers (1)

Dirk is no longer here
Dirk is no longer here

Reputation: 368271

Note that the file is called Makefile.in -- this signifies that it is input to another file (or transformation).

In short, configure will run and determine, say, where the relevant include files are for @mathinc -- likely some math headers. After you run configure it will produce Makefile (no trailing .in) based on what it finds. Do inspect that file.

configure scripts are created in a system called autoconf which, like all build systems, has its fans and its haters. There are some decent tutorials as for example this one.

Upvotes: 2

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