Please install the HP WDB bundled with the compiler or a more recent version of wdb to get full functionality.

The default behavior of the +check=malloc option can be changed by users providing their own rtcconfig file. The user specified rtcconfig file can be in the current directory or in a directory specified by the GDBRTC_CONFIG environment variable. The default configuration used by the +check=malloc option is:

check_bounds=1;check_free=1;scramble_block=1;

abort_on_bounds=1;abort_on_bad_free=1;abort_on_nomem=1; check_leaks=1;min_leak_size=0;check_heap=0; frame_count=4;output_dir=.;

When +check=bounds:pointer is also turned on, it can check freed memory read/write. But the check needs to retain freed memory which is not turned on by default. To turn on the feature, set the following environment variable at runtime:

RTC_MALLOC_CONFIG="retain_freed_blocks=1"

Or add "retain_freed_blocks=1" to the rtcconfig file. When malloc failes to allocate specified memory, the runtime system will free the retained freed memory and try to allocate memory.

For a description for the above configuration parameters and the full list of other parameters, please refer to the HP WDB debugger documentation.

+check=stack[:frame:variables:none]

The +check=stack[:frame:variables:none] option enables runtime checks to detect writes outside stack boundaries. Markers are placed before and after the whole stack frame and around some stack variables. On procedure exit, a check is done to see if any marker has been overwritten. If any stack check fails, an error message and stack trace is written to stderr and the program is aborted. The stack checks are not performed for an abnormal exit from the procedure (for example, using longjmp, exit, abort, or exception handling).

+check=stack:frame

This option enables runtime checks for illegal writes from the current stack frame that overflow into the previous stack frame.

+check=stack:variables

This option enables runtime checks for illegal writes to the stack just before or after some variables on the stack. This includes array, struct/class/union, and variables whose address is taken. It also includes the overflow check for the stack frame (+check=stack:frame). In addition to the above checks, this option causes the whole stack to be initialized to a "poison" value, which can help detect the use of uninitialized variables on the stack.

+check=stack:none

This option disables all runtime checks for the stack.

+check=stack

The +check=stackoption without any qualifiers is equivalent to +check=stack:variables at optimization levels 0 and 1. It is equivalent to +check=stack:frame for optimization level 2 and above.

+check=thread

The +check=thread option enables the batch-mode thread-debugging features of HP WDB 5.9 or later, and can detect the following thread-related conditions:

•The thread attempts to acquire a nonrecursive mutex that it currently holds.

•The thread attempts to unlock a mutex or a read-write lock that it has not acquired.

•The thread waits (blocked) on a mutex or read-write lock that is held by a thread with a different scheduling policy.

80 Command-Line Options