# - Check if the prototype for a function exists.
# CHECK_PROTOTYPE_EXISTS (FUNCTION HEADER VARIABLE)
#
#  FUNCTION - the name of the function you are looking for
#  HEADER - the header(s) where the prototype should be declared
#  VARIABLE - variable to store the result
#

INCLUDE(CheckCXXSourceCompiles)

MACRO(CHECK_PROTOTYPE_EXISTS _SYMBOL _HEADER _RESULT)
   set(_INCLUDE_FILES)
   foreach(it ${_HEADER})
      set(_INCLUDE_FILES "${_INCLUDE_FILES}#include <${it}>\n")
   endforeach(it)

   set(_CHECK_PROTO_EXISTS_SOURCE_CODE "
${_INCLUDE_FILES}
int main()
{
#ifndef ${_SYMBOL}
   int i = sizeof(&${_SYMBOL});
#endif
  return 0;
}
")
   CHECK_CXX_SOURCE_COMPILES("${_CHECK_PROTO_EXISTS_SOURCE_CODE}" ${_RESULT})
ENDMACRO(CHECK_PROTOTYPE_EXISTS _SYMBOL _HEADER _RESULT)