Where Does the C/C++ Compiler Find Header Files?

where-does-compiler-find-headers.md

Where does the C/C++ Compiler Find Header Files?

Ask the Preprocessor

GNU

# GNU C++ preprocessor
`gcc -print-prog-name=cc1plus` -v
# GNU C preprocessor
`gcc -print-prog-name=cpp` -v

Clang

# C
clang -H hello.c
# CPP
clang++ -H hello.cpp

Ask the Compiler

# C
gcc -v hello.c
clang -### hello.c
# C++
gcc++ -### hello.cpp
clang++ -### hello.cpp

Read the Manual

• GNU CPP 13.2: 2.3 Search Path