CMAKE string options

Question

How to specify string option in CMakeLists.txt? Syntax option(OPT1 "Helpstring" ON) works perfectly for boolean options but I would like to have few string options like -march= argument passed to gcc.

Answer 1

Any user-settable variable can be defined with set:

set(OPT2 "Default" CACHE STRING "Helpstring")

so -march would be something like:

set(ARCH "" CACHE STRING "Architecture to tell gcc to optimize for (-march)")