Question

I am concatenating several strings. When running the program it gives me a Debug Assertion Failed! message which says Expression: (L”String is not null terminated” && 0).

All strings seem to be NULL terminated, but I am not sure what else could it be. Any ideas?

I am including the code excerpt where it triggers the problem.

void foo(){
    ....
    char adj_command_string[COMMAND_SIZE];
    reconstructCommand(&command_parameters, adj_command_string);
    ....
}


void reconstructCommand(command* command_data, char* adjusted_string){

    char partial_string[COMMAND_SIZE];
    char string_rep[COMMAND_SIZE];

    if (command_data->g_code.new_value){
        sprintf_s(string_rep, COMMAND_SIZE, "G%d ", command_data->g_code.value);
        strcat_s(partial_string, COMMAND_SIZE, string_rep);
    }

    // If position changed, include change in command.
    if (command_data->pos.X.value){
        sprintf_s(string_rep, COMMAND_SIZE, "X%.4f ", command_data->pos.X.value);
        strcat_s(partial_string, COMMAND_SIZE, string_rep);
    }

    if (command_data->pos.Y.value){
        sprintf_s(string_rep, COMMAND_SIZE, "Y%.4f ", command_data->pos.Y.value);
        strcat_s(partial_string, COMMAND_SIZE, string_rep);
    }

    if (command_data->pos.Z.value){
        sprintf_s(string_rep, COMMAND_SIZE, "Z%.4f ", command_data->pos.Z.value);
        strcat_s(partial_string, COMMAND_SIZE, string_rep);
    }

    if (command_data->pos.A.value){
        sprintf_s(string_rep, COMMAND_SIZE, "A%.4f ", command_data->pos.A.value);
        strcat_s(partial_string, COMMAND_SIZE, string_rep);
    }

    // If Feedrate originally included, include it in modified command
    if (command_data->feedrate.new_value){
        sprintf_s(string_rep, COMMAND_SIZE, "F%.4f ", command_data->feedrate.value);
        strcat_s(partial_string, COMMAND_SIZE, string_rep);
    }

    // If spindle speed originally included, include it in modified command
    if (command_data->speed.new_value){
        sprintf_s(string_rep, COMMAND_SIZE, "S%.4f ", command_data->speed.value);
        strcat_s(partial_string, COMMAND_SIZE, string_rep);
    }

    adjusted_string = partial_string;
}

Answer 1

I am not sure if this is the source of the problem but:

adjusted_string = partial_string;

Will not copy the contents of partial_string into adjusted_string. Use strcpy() or some other similar mechanism and ensure that adjusted_string is null terminated.