Assert(3)
·
Usage:
#include <assert.h>
void assert(scalar
expression);
·
Use assert religiously any time you know certain relationships that MUST hold between variables
to another or a variable to a constant.
·
It is helpful for the programmer,
not the user.
o Sample output: “Assertion failed in file foo.c,
function do_bar, line 1287”.
·
Leave in your code FOREVER
o If symbol NDEBUG is defined, the macro goes to nothing.
Simple TRACE macro
- Useful so your fprintf(stderr,…)
is not hard-coded in your code
- Basically what is present in
MS Visual Studio C++ (and many other compilers no doubt…)
- Code: trace.h
More Complex DEBUG
Macro
- TRACE gives you EVERY
output ALL THE TIME.
- This debug macro setup
lets you turn on and of individual debug “topics” (up to 32) –
MUCH finer-grained control over the debug output
- Implementation: have a
debug flag bit array set at runtime in an environment variable to change
what debug printouts happen without recompiling your code
- Also can have other
information printed out on the debug line before the debug statement
(thread ID, thread state, …)
- Template: DEBUG(FLAGS, FORMAT, a1, a2, a3);
- Real example: DEBUG (D_SPAWN, "r%06lX spawn p%06lX", CUR_RES,
pr, 0);
- Can also use multiple
flags in code: DEBUG(D_FLAG2|D_FLAG2,
…)
- Must first initialize
at startup by calling sr_init_debug()
- Code (note: details
not testable (they are hairy!), main ideas/benefits are): debug.h, debug.c
- Note: it was coded
before __VA_ARGS__ was
defined for macros, but for portability they would still probably use
this version