Assertions
[Global data and functions]

Detailed Description

Macros to define assertions, supposedly for debugging purpose.

#include <qgarlib/assert.H>

Assertions are compiled into a program:

either when providing the (preprocessor) option -DQGARDEBUG in the command line invoking the compiler,

or when defining QGARDEBUG as a macro name in the source code, before the inclusion of the assert.H header file:

...
#define QGARDEBUG // To be imperatively placed ahead of the #include below
...
...
#include <qgarlib/assert.H>
...

Assertions are used in a similar way as standard macro assert() (see standard header file assert.h).

void qgarAssert(int EX)
If EX is false, print a diagnostic message on the standard error output and abort.
Execution of a user-defined function may be substituted for abortion: See macro setQgarAssertHandler.
void qgarAssertAndEval(EX, EX2)
Same as qgarAssert(EX), but EX2 is evaluated before abortion.
void qgarAssertAndCatch(EX, EX2)
Same as qgarAssertAndEval(EX, EX2), but does not abort: Execution proceeds sequentially when returning from the macro.
void setQgarAssertHandler(void (*HANDLER)(int))
Substitute the execution of a user-defined function for abortion in case of assertion failer. The function must conform to the following pattern:
```
#include <qgarlib/assert.H>

...

void userHandler(int i)
{
  signal(SIGABRT, SIG_IGN);
  ...
  ...  // user-specific code
  ...
  signal(SIGABRT, userHandler);
}
```
See macro resetQgarAssertHandler.
void resetQgarAssertHandler()
Restore abortion in case of assertion failer. See macro setQgarAssertHandler.