# CheckStructHasMember

Check if the given struct or class has the specified member variable

check_struct_has_member

      check_struct_has_member(<struct> <member> <headers> <variable>
                              [LANGUAGE <language>])

  Check that the struct or class `<struct>` has the specified `<member>` after including the given header(s) `<headers>` where the prototype should be declared. Specify the list of header files in one argument as a semicolon-separated list. The result is stored in an internal cache variable `<variable>`.

  The options are:

  `LANGUAGE <language>`

    Use the `<language>` compiler to perform the check. Acceptable values are `C` and `CXX`. If not specified, it defaults to `C`.

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

> `CMAKE_REQUIRED_FLAGS`

>   String of additional flags to pass to the compiler. The string must be space-delimited--a ;-list will not work. The contents of `CMAKE_<LANG>_FLAGS` and its associated configuration-specific variable are automatically added to the compiler command before the contents of `CMAKE_REQUIRED_FLAGS`.

> `CMAKE_REQUIRED_DEFINITIONS`

>   A ;-list of compiler definitions of the form `-DFOO` or `-DFOO=bar`. A definition for the name specified by `<resultVar>` will also be added automatically.

> `CMAKE_REQUIRED_INCLUDES`

>   A ;-list of header search paths to pass to the compiler. These will be the only header search paths used--the contents of the `INCLUDE_DIRECTORIES` directory property will be ignored.

> `CMAKE_REQUIRED_LINK_OPTIONS`

>   Added in version 3.14.

>   A ;-list of options to add to the link command (see `try_compile()` for further details).

> `CMAKE_REQUIRED_LIBRARIES`

>   A ;-list of libraries to add to the link command. These can be the name of system libraries or they can be Imported Targets (see `try_compile()` for further details).

> `CMAKE_REQUIRED_LINK_DIRECTORIES`

>   Added in version 3.31.

>   A ;-list of libraries search paths to pass to the linker (see `try_compile()` for further details).

> `CMAKE_REQUIRED_QUIET`

>   Added in version 3.1.

>   If this variable evaluates to a boolean true value, all status messages associated with the check will be suppressed.

## Example

    include(CheckStructHasMember)

    check_struct_has_member("struct timeval" tv_sec sys/select.h
                            HAVE_TIMEVAL_TV_SEC LANGUAGE C)