The goal of clibrary is to create/simulate an environment of programming oriented object in C and provides many feature from c++ and Javascript.
The idea is to substitute the use of native types like char * by autonomous object.
Clibrary also provides an efficient debugger to reduce debugging sessions...
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Programming oriented object
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Provide all basics types as object
Type Functions String new_string, string_destroy, at, clear, size, compare, copy, empty, insert, to_int, append, assign, find, print -
Provide many features from c++ and javascript
The first main part of clibrary is the debugger. It provides some functions and informations for your programs
Exception are a very powerful way to program error safe programs. Exceptions let you write straight code without testing for errors at each statement. You can meet this type d'instruction in programming language like c++, java or c#
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try
{
...
/* error prone statements */
...
}
catch(SomeExceptionType e)
{
...
/* do something intelligent here*/
...
}
...There is no try catch statement in C but there are some ways to reproduce their effects. The solution here is not a fully functional try-throw-catch system. It does not forward exceptions from one block to one more external if no handler is provided. Real exception mechanisms need run-time support. To do that, we'll explore the potentiality of longjmp and setjmp function with a non trivial example.
longjmp and setjmp are defined in setjmp.h header file...
#include <setjmp.h>setjmp take a jmp_buf type variable as only input. It returns 0 when invoked directly and when longjmp is invoked with the same jmp_buf variable. It returns the value passed as second argument of longjmp.
Example of basic try-throw-catch:
#include <stdio.h>
#include <setjmp.h>
#define TRY do{ jmp_buf ex_buf__; switch( setjmp(ex_buf__) ){ case 0:
#define CATCH(x) break; case x:
#define ETRY } }while(0)
#define THROW(x) longjmp(ex_buf__, x)
#define EXCEPTION (1)
int main(int argc, char** argv)
{
TRY {
printf("In Try Statement\n");
THROW(BAR_EXCEPTION);
printf("I do not appear\n");
} CATCH(EXCEPTION) {
printf("Got Exception!\n");
} ETRY;
return (0);
}
Then here is a concrete example of the use of the try-throw-catch:
#include "includes/index.h"
#include <string.h>
static jmp_buf ex_buf;
static void assign_c(string_t *this, register char const *restrict s)
{
if (is_undefined(this->str) || is_undefined(s)) THROW(3);
string_destroy(this);
this->str = (char *)s;
this->length = my_strlen(s);
}
void (assign)(string_t *this, string_t const *restrict str, global_info_t infos)
{
TRY {
my_assert(this != NULL, infos, ASSERT_INFO(DESC_ERR_THIS_UNDEFINED,
ERR_TYPE, FAIL_EXEC), ex_buf);
my_assert(str != NULL, infos, ASSERT_INFO(DESC_ERR_STR_UNDEFINED,
ERR_TYPE, FAIL_EXEC), ex_buf);
assign_c(this, str->str);
} CATCH(1) {
return;
} CATCH(3) {
my_warning_assert(!is_undefined(this->str), infos, ASSERT_INFO(
DESC_ERR_STR_UNDEFINED, ERR_TYPE, FAIL_FUNC_EXEC), ex_buf);
my_warning_assert(!is_undefined(str->str), infos, ASSERT_INFO(
DESC_ERR_STR_UNDEFINED, ERR_TYPE, FAIL_FUNC_EXEC), ex_buf);
} ETRY;
}Assign function from string object is used to assign a new value to your object. Some errors could occurred like those above. (my_assert and my_warning_assert functions are the next points of this part.).
In this example, assign_c is a possible cancellation point, therefore there is a THROW inside which throw exception 3 if this->str or s are undefined.
In this case, CATCH(3) is called and a jump is made from the call throw to the catch in question.
In this part, we are talking about the error display. As you saw before, my_assert and warning_assert are used to process the error. 4 arguments must be provided:
- Assertion => expression to evaluate
- Infos => structure contains all information about the error:
__LINE____FILE__and so on... - ASSERT_INFO container all information about the type of error
- ex_buf variable to catch throw
my_warning_assertfunction display a warning with the type of error. The function process is aborted but the program continues.my_assertfunction display an error with the type of error. The function is aborted and the programexit(84)