Check if a symbol exists as a function, variable, or macro

CHECK_SYMBOL_EXISTS(<symbol> <files> <variable>)

Check that the <symbol> is available after including given header <files> and store the result in a <variable>. Specify the list of files in one argument as a semicolon-separated list.

If the header files define the symbol as a macro it is considered available and assumed to work. If the header files declare the symbol as a function or variable then the symbol must also be available for linking. If the symbol is a type or enum value it will not be recognized (consider using CheckTypeSize or CheckCSourceCompiles). If the check needs to be done in C++, consider using CHECK_CXX_SYMBOL_EXISTS(), which does the same as CHECK_SYMBOL_EXISTS(), but in C++.

The following variables may be set before calling this macro to modify the way the check is run:

CMAKE_REQUIRED_FLAGS = string of compile command line flags
CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar)
CMAKE_REQUIRED_INCLUDES = list of include directories
CMAKE_REQUIRED_LIBRARIES = list of libraries to link