many suggestion: what you wrote is never going to do what you want.
1. i don't see the point of declaring bytes_sent and bytes_read as arguments to the DisplayRS232Error() function: those values are never used in the body of the function.
2. where is RS232Error declared ? it seems like it is a global variable. it would be much more correct to pass it as an argument (that's about the only value on which this function depends)
3. you open the log file at the beginning of the function. that's not efficient, the file will be opened each time there is an RS232 error. it would be better to open the file once at the beginning of the program and close it properly at the end.
4. you open the file with a "w" mode: read the documentation for the fopen() function. the file will be erased each time you call the DisplayRS232Error(), thus losing any previous error. i am pretty sure you want to use mode "w+" which append to the file if it already exists.
5. you open the log file but you do never close it ! remember to always free the resource you are using, files are no exception.
beside this, i will add:
6. a log is useless without other informations, like the date and time an error occured.
7. do you ever test your code before posting ? point 4 is critical, and running your software only 2 times would have showed this problem. take the time to review your code, compile it, test it, debug it, and try to correct as much problems as you can by yourself (it is much more rewarding) before posting another question. you could have avoided your last 2 posts if you had done your job correctly.
