Simple Assert Library

Summary

One-header, zero-dependency simple assertion lib for restricted environments.

Usage

Use ASSERT() macro to check the specified condition. If condition falls, the assertion message appears on stdout and you may do a specific reaction (return, close rosource or smth. else).

int resize(unsigned int newSize) {  
    /* Simple checking of variable */

    // check with reaction (return from routine)
    ASSERT(0 < newSize && newSize < 100) return -1; 

    // check with reaction and message
    ASSERT(newSize != 10, "size should not be equal to 10, but received: %d", newSize) {
    	/* Free some resources, close files etc. */
    	return -2;
    }

    
    /* Do something useful */

    return 0; // all is Ok
}

See more examples in examples folder.

Also there is an alias for ASSERT() macro named VERIFY() (it's handy in situations when ASSERT() is already in use).

Printing messages

By default ASSERT(condition, msg) prints message (through SASERT_PRINTF) "Assertion condition failed" and any additional message msg that specified as a second parameter.

To suppress message - use the empty string as a second parameter ASSERT(i > 15, ""). This useful while assert condition happens frequently or is a part of normal program flow to prevent flooding the output with a lot of assertion messages.

If you don't need any output at all - set SIMPLE_ASSERT_SILENT 1 in src/SimpleAssert.h.

If your platform doesn't support printf you may define your own SIMPLE_ASSERT_PRINTF macro to make formatted output. For example, for Arduino-based platforms (Arduino, ESP8266, ESP32 etc.) use #define SIMPLE_ASSERT_PRINTF Serial.printf

Special case: check zero return

Many functions from std and other lib returns 0 on success and some error code otherwise. Simple Assert Lib includes special macro CHECK0(function, msg) for this case.

In a nutshell CHECK0() is a special kind of ASSERT() that checks return value of the function and prints it if return is non-zero. For example

CHECK0(foo()) return -3;

prints value, returned by foo() and returns with -3, if foo() value is non-zero. You may add a custom message or suppress message at all with CHECK0() in the same ways as with the ASSERT().

Also there is an alias for CHECK0() named IFNOT0(), for using in the statements with complex reaction - to improve a code readability (see below).

If you need to retrieve the error code, returned by function inside CHECK0(), you may use a special helper CHECK0_RES:

IFNOT0(readFile(fileName, buf)) {
   if (CHECK0_RES == ENOMEM)
       printf("Out of memory\n");
   else if (CHECK0_RES == EACCES)
       printf("Permission denied\n");
   else
       printf("Unknown error\n");
   
}

Special case: check True

Many functions in Arduino-based environments return true (non-zero) on success and false (zero) otherwise. Simple Assert Lib includes special macro CHECKOK(function, msg) for this case. The usage is the same as ASSERT() and CHECK0().

Also there is an alias for CHECKOK() macro named IFFALSE() - this may improve a code readability:

IFFALSE (connectServer(address), "Failed connect to: %s", address) {
    errCount++;
    reconnectionScheduled = true;    
    return;
}

Authors

1. dRKr, Sinai RnD (info@sinai.io)