[ts-7000] Re: [ts7400] program crash when writing GPIO data register

["mccarl1978" <>]

--- In  "yuezhu92" <> wrote:
> int fd = open("/dev/mem", O_RDWR|O_SYNC);
> 
> char* page1   = (char *)mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 
> 0x12c00000);
> 
> page1[3] = 0xff; //error! program crash
> 

You should add some error checking code to check the return values of the 
'open' and 'mmap' calls, to see which one is failing. And then you can check 
the value of a variable called 'errno' to get more information on why a call is 
failing. You can use 'perror' for this. For example:


int fd = open("/dev/mem", O_RDWR|O_SYNC);
if(fd == -1)
{
    perror("MyFunction (open)");
    return; //exit(-1);
}

char* page1   = (char *)mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 
0x12c00000);
if(page1 == (char *) MAP_FAILED)
{
    perror("MyFunction (mmap)");
    return; //exit(-1);
}

page1[3] = 0xff; //error! program crash




Cheers
Phil



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