Thread: Core Dump with Variable Arguments

Code:

I have written the following code which accepts variable arguments:

void dprintf(FILE *fp,char *fmt,...)
{
        char OldMsg[BUFSIZ];
        va_list lArgs;

        if(fmt && *fmt)
        {
            fmt[strlen(fmt)-1]='\0'; /* Remove ending \n */
            va_start(lArgs, fmt);
            vsprintf(OldMsg, fmt, lArgs);
            va_end(lArgs);
            fprintf(fp, "%s at %s_%02d\n", 
                        OldMsg, Run.date, Run.hour);
        }
}

I am calling the function as follows:

dprintf(flog,"\t%s(%s): Unable to insert node\n", 
             program_name, sccs_ver);

My program core dumps because of this routine. Can anyone tell me what's wrong with it? I have written similar functions in the past and never had an issue.

Thank you very much. I did realize that it throws away the last char unconditionally.

The whole reason I created the routine was because their were a million fprintf's in the program and I needed a way to easily add a date/time stamp to the end of the messages without having to do a bunch of manual work. I verified ahead of time that all the previous calls ended in a \n and will always end that way. I was so focused on something being wrong with the var message part I overlooked the const pointer issue - so thank you all very much.