xref: /freebsd/contrib/libevent/cmake/CheckConstExists.cmake (revision b50261e21f39a6c7249a49e7b60aa878c98512a8) 
1*b50261e2SCy Schubertinclude(CheckCSourceCompiles)
2*b50261e2SCy Schubert
3*b50261e2SCy Schubertmacro(check_const_exists CONST FILES VARIABLE)
4*b50261e2SCy Schubert  if (NOT DEFINED ${VARIABLE})
5*b50261e2SCy Schubert    set(check_const_exists_source "")
6*b50261e2SCy Schubert    foreach(file ${FILES})
7*b50261e2SCy Schubert      set(check_const_exists_source
8*b50261e2SCy Schubert          "${check_const_exists_source}
9*b50261e2SCy Schubert          #include <${file}>")
10*b50261e2SCy Schubert    endforeach()
11*b50261e2SCy Schubert    set(check_const_exists_source
12*b50261e2SCy Schubert        "${check_const_exists_source}
13*b50261e2SCy Schubert        int main() { (void)${CONST}; return 0; }")
14*b50261e2SCy Schubert
15*b50261e2SCy Schubert    check_c_source_compiles("${check_const_exists_source}" ${VARIABLE})
16*b50261e2SCy Schubert
17*b50261e2SCy Schubert    if (${${VARIABLE}})
18*b50261e2SCy Schubert      set(${VARIABLE} 1 CACHE INTERNAL "Have const ${CONST}")
19*b50261e2SCy Schubert      message(STATUS "Looking for ${CONST} - found")
20*b50261e2SCy Schubert    else()
21*b50261e2SCy Schubert      set(${VARIABLE} 0 CACHE INTERNAL "Have const ${CONST}")
22*b50261e2SCy Schubert      message(STATUS "Looking for ${CONST} - not found")
23*b50261e2SCy Schubert    endif()
24*b50261e2SCy Schubert  endif()
25*b50261e2SCy Schubertendmacro(check_const_exists)
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