c++ - Does adding many -isystem include directives slow down the compilation process significantly? -

for our software project, have around 15 third party library dependencies. suppress warnings in these third party libraries using -isystem include directive.

our software project consists of more 10 executables , libraries, each having dependencies on subset of third party libraries. compile clang on mac.

an easy way disable third party warnings projects in our build system include third party libraries in projects -isystem.

the alternative separately define each of our projects -isystem directive. more work set , blow configurations of project files, third party libraries used included.

i'd prefer go first option because it's not work, not sure if slow down compilation process?

this flag slowdown standard headers search because prior each standard header found search in directories. so, depends on how many such directories add , how many standard headers use. each standard header impact summ of:

time ls your_dir >> /dev/null 2>&1 

for each added directory.