%none

Perform none of the -xcheck checks.

%all

Perform all of the -xcheck checks.

stkovf

Turns on stack-overflow checking.-xcheck=stkovf adds a runtime check for stack overflow of the main thread in a singly-threaded program as well as slave-thread stacks in a multithreaded program. If a stack overflow is detected, a SIGSEGV is generated. If your application needs to handle a SIGSEGV caused by a stack overflow differently than it handles other address-space violations, see sigaltstack(2).

no%stkovf

Turns off stack-overflow checking. 

init_local

Initialize local variables. 

no%init_local

Do not initialize local variables.