...Validate WCS Information

Once you have read WCS information from a dataset, as in 3.4, you may wish to check that you have been successful. The following will detect and classify the things that might possibly go wrong:

#include <string.h>

...

if ( !astOK ) {
   <an error occurred (a message will have been issued)>
} else if ( wcsinfo == AST__NULL ) {
   <there was no WCS information present>
} else if ( strcmp( astGetC( wcsinfo, "Class" ), "FrameSet" ) ) {
   <something unexpected was read (i.e. not a FrameSet)>
} else {
   <WCS information was read OK>
}

For more information about detecting errors in AST functions, see 4.15. For details of how to validate input data read by AST, see 15.6 and 17.4.