C preprocessor versus C compiler

Question

If I tell the C preprocessor to # include the file and use CPPFLAGS to find the file I need, then the file is already included, right? What, if any, tells the C compiler about the same include directory with CFLAGS?

Answer 1

I do not think it will be useful.

implicit rules make indicates that it is CFLAGSused only when compiling C programs (from .c to .o). The value is CPPFLAGSalso added to the compiler command line.

CPPFLAGS also used in the following rules:

• Compilation of programs in C ++
• Compiling Fortran and Ratfor
• Preprocessing Fortran and Ratfor.
• Lint C, Yacc Lex

CPPFLAGS , CFLAGS, , -I CFLAGS, CPPFLAGS.

, Makefile , CFLAGS , CPPFLAGS, .