Check if a symbol exists as a function, variable, or macro in
check_cxx_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.
check_cxx_symbol_exists()can be used to check for symbols as seen by the C++ compiler, as opposed to
check_symbol_exists(), which always uses the
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, enum value, or C++ template it will not be recognized: consider using the
This command is unreliable when
<symbol> is (potentially) an overloaded
function. Since there is no reliable way to predict whether a given function
in the system environment may be defined as an overloaded function or may be
an overloaded function on other systems or will become so in the future, it
is generally advised to use the
CheckCXXSourceCompiles module for
checking any function symbol (unless somehow you surely know the checked
function is not overloaded on other systems or will not be so in the
The following variables may be set before calling this macro to modify the way the check is run:
string of compile command line flags.
a ;-list of macros to define (-DFOO=bar).
a ;-list of header search paths to pass to the compiler.
New in version 3.14: a ;-list of options to add to the link command.
New in version 3.1: execute quietly without messages.
include(CheckCXXSymbolExists) # Check for macro SEEK_SET check_cxx_symbol_exists(SEEK_SET "cstdio" HAVE_SEEK_SET) # Check for function std::fopen check_cxx_symbol_exists(std::fopen "cstdio" HAVE_STD_FOPEN)