C++ exception

Question

Hi, 
 I'm using Segger Embedded Studio (with gcc naturally). The standard C++ exception handling doesn't work: exceptions are not caught by exception handler. Is there a way to enable normal C++ behaviour? 
 Thanks, 
 Daniel

Øyvind · Accepted Answer

The Hard Fault handler is based on ARM 's own exception handler: https://developer.arm.com/docs/dui0553/latest/the-cortex-m4-processor/exception-model/exception-handlers and this handles all CPU specific faults that can occur, but should not. ARM describes these faults here: https://developer.arm.com/docs/dui0553/latest/the-cortex-m4-processor/fault-handling To learn more about the ARM Instruction set (Assembly) please see this link . 
 T he Error Module handles application specific errors, it uses the app_error_fault_handler for handling application and SoftDevice errors and is the default in our SDK. 
 Daniel Reisfeld said: 1. Do I need to compile this as part of my project? 
 No, you do not need to implement it, but we highly recommend it. 
 Daniel Reisfeld said: 2. Does implementing HardFault_c_handler interfere with softdevice? 
 When certain unrecoverable errors occur within the application or SoftDevice, the fault handler will be called. This fault handler function is passed to the SoftDevice during initialization ( sd_softdevice_enable() ) HardFault should never happen; it might happen because of a code error, electromagnetic interference (EMI) near the device, or glitches on power lines. In this case, the microcontroller will hang in an endless loop until the next reset, unless a watchdog is used in the code. 
 Daniel Reisfeld said: 3. What is the uint32_t * parameter passed to HardFault_c_handler? 
 This is the program stack pointer address, used in the HardFault_C_handler to indicate what caused the error: [0] = "The processor has attempted to execute an undefined instruction",
 [1] = "The processor attempted a load or store at a location that does not permit the operation",
 [2] = NULL,
 [3] = "Unstack for an exception return has caused one or more access violations",
 [4] = "Stacking for an exception entry has caused one or more access violations",
 [5] = "A MemManage fault occurred during floating-point lazy state preservation",
 [6] = NULL,
 [7] = NULL,
 [8] = "Instruction bus error",
 [9] = "Data bus error (PC value stacked for the exception return points to the instruction that caused the fault)",
 [10] = "Data bus error (return address in the stack frame is not related to the instruction that caused the error)",
 [11] = "Unstack for an exception return has caused one or more BusFaults",
 [12] = "Stacking for an exception entry has caused one or more BusFaults",
 [13] = "A bus fault occurred during floating-point lazy state preservation",
 [14] = NULL,
 [15] = NULL,
 [16] = "The processor has attempted to execute an undefined instruction",
 [17] = "The processor has attempted to execute an instruction that makes illegal use of the EPSR",
 [18] = "The processor has attempted an illegal load of EXC_RETURN to the PC, as a result of an invalid context, or an invalid EXC_RETURN value",
 [19] = "The processor has attempted to access a coprocessor",
 [20] = NULL,
 [21] = NULL,
 [22] = NULL,
 [23] = NULL,
 [24] = "The processor has made an unaligned memory access",
 [25] = "The processor has executed an SDIV or UDIV instruction with a divisor of 0", Kind regards, Øyvind

C++ exception

Top Replies