Posted by Zaphod on 2020-05-27 00:11

First - use snprintf() instead of sprintf(). While THIS example with THIS specific value (101) will not overflow your 5 byte buffer, it is a good habit to get in to. For example:

sprintf( Holding, sizeof(Holding), “%i”, Input );

Second - can you be more specific about what “crash” means? Does your code end up somewhere you don’t expect, like a fault handler? Note that by default, all fault handlers are simply an empty loop, which usually ends up as a “jump to self” instruction in the startup code just after the call to main(). You may need real code in your fault handlers, or at least a breakpoint so you can inspect the fault registers to see what caused the fault.

Is that code snippet you showed us REALLY the entire function? Or is there more to it?

Posted by sakula on 2020-06-02 11:22

STM32 crashes when using the sprintf function

1. Software environment: Keil MDK 5.15
2. Hardware environment: STM32F103C8T6 minimum system
Today, when I was programming STM32, I made a strange mistake. The program was blocked in a function. After looking it up for a long time, I found that it was blocked in the sprintf function!!
Serial port printed the first sentence, the card died, the next sentence did not execute to.

The reasons are as follows

__’‘void foo(char *path)
{
...
printu(“enter dir:%s\r\n”, path);
sprintf(path + i, “/%s”, fn);
printu(“enter1 dir:%s\r\n”, path);
...

}

call foo(“0:”);’‘__

The access to the path array is out of bounds! When calling, write as follows:

__’‘char path10 =”0:”;
foo(path);’‘__