kassert

This module has four macros and is header only. The four macros are as follows:

kassert(cond, return_code)

This macro should be used in non-void functions for assertions that don’t need custom error messages.

Example Usage:

#include "kassert.h"
#include "kstdio.h"

int func(void) {
    kassert(1 == 2, -1);
}

int main(void) {
    terminal_initialize();
    const int x = func();
    kprintf("%i\n", x);
    return 0;
}

Output:

[file: foo/bar.c :: line: 5]: Condition Failed: 1==2

-1

kassert_void(cond)

This macro should be used in void functions for assertions that don’t need custom error messages.

Example Usage:

#include "kassert.h"

void func(void) {
    kassert_void(1 == 2);
}

int main(void) {
    terminal_initialize();
    func();
    return 0;
}

Output:

[file: foo/bar.c :: line: 5]: Condition Failed: 1==2

kassert_message(cond, message, return_code)

This macro should be used in non-void functions for assertions that need custom error messages.

Example Usage:

#include "kassert.h"
#include "kstdio.h"


int func(void) {
    kassert_message(1 == 2, "arithmetic is broken", -1);
}

int main(void) {
    terminal_initialize();
    const int x = func();
    printf("%i\n", x);
    return 0;
}

Output:

arithmetic is broken

-1

kassert_message_void(cond, message)

This macro should be used in void functions for assertions that need custom error messages.

Example Usage:

#include "kassert.h"

void func(void) {
    kassert_message_void(1 == 2, "arithmetic is broken");
}

int main(void) {
    terminal_initialize();
    func();
    return 0;
}

Output:

arithmetic is broken

Reason for the Naming

The k prefix to the file and the functions is the naming convention for this implementation/version of libc including for non-standard functions and extensions.

The reason why is that tests are run in userland and linked against glibc. So, to be able to test our libc on our host development machines, the prefix is needed.

Differences with Standard <assert.h> in libc

These assertions do NOT cause terminate to be invoked. It is often preferable to have assertions, but not terminate in the kernel.

All of these assertions will log to standard output (via the vga driver) the error message and then return their error code that was passed in (or just return; in the case of the void versions).

Miscellaneous Notes

All 4 macros will print a newline character after the message even if the custom message had no newline at the end.