CheckSymbolExists¶
Provides a macro to check if a symbol exists as a function, variable,
or macro in C
.
-
check_symbol_exists
¶ 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.<variable>
will be created as an internal cache variable.
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 (so intrinsics may not be detected).
If the symbol is a type, enum value, or intrinsic it will not be recognized
(consider using CheckTypeSize
or CheckCSourceCompiles
).
If the check needs to be done in C++, consider using
CheckCXXSymbolExists
instead.
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
a ;-list of macros to define (-DFOO=bar).
CMAKE_REQUIRED_INCLUDES
a ;-list of header search paths to pass to the compiler.
CMAKE_REQUIRED_LINK_OPTIONS
a ;-list of options to add to the link command.
CMAKE_REQUIRED_LIBRARIES
a ;-list of libraries to add to the link command. See policy
CMP0075
.CMAKE_REQUIRED_QUIET
execute quietly without messages.
For example:
include(CheckSymbolExists)
# Check for macro SEEK_SET
check_symbol_exists(SEEK_SET "stdio.h" HAVE_SEEK_SET)
# Check for function fopen
check_symbol_exists(fopen "stdio.h" HAVE_FOPEN)