xref: /freebsd-src/contrib/ntp/sntp/libevent/cmake/CheckConstExists.cmake (revision a466cc55373fc3cf86837f09da729535b57e69a1) 
1*a466cc55SCy Schubertinclude(CheckCSourceCompiles)
2*a466cc55SCy Schubert
3*a466cc55SCy Schubertmacro(check_const_exists CONST FILES VARIABLE)
4*a466cc55SCy Schubert  if (NOT DEFINED ${VARIABLE})
5*a466cc55SCy Schubert    set(check_const_exists_source "")
6*a466cc55SCy Schubert    foreach(file ${FILES})
7*a466cc55SCy Schubert      set(check_const_exists_source
8*a466cc55SCy Schubert          "${check_const_exists_source}
9*a466cc55SCy Schubert          #include <${file}>")
10*a466cc55SCy Schubert    endforeach()
11*a466cc55SCy Schubert    set(check_const_exists_source
12*a466cc55SCy Schubert        "${check_const_exists_source}
13*a466cc55SCy Schubert        int main() { (void)${CONST}; return 0; }")
14*a466cc55SCy Schubert
15*a466cc55SCy Schubert    check_c_source_compiles("${check_const_exists_source}" ${VARIABLE})
16*a466cc55SCy Schubert
17*a466cc55SCy Schubert    if (${${VARIABLE}})
18*a466cc55SCy Schubert      set(${VARIABLE} 1 CACHE INTERNAL "Have const ${CONST}")
19*a466cc55SCy Schubert      message(STATUS "Looking for ${CONST} - found")
20*a466cc55SCy Schubert    else()
21*a466cc55SCy Schubert      set(${VARIABLE} 0 CACHE INTERNAL "Have const ${CONST}")
22*a466cc55SCy Schubert      message(STATUS "Looking for ${CONST} - not found")
23*a466cc55SCy Schubert    endif()
24*a466cc55SCy Schubert  endif()
25*a466cc55SCy Schubertendmacro(check_const_exists)
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