STM fgets character limit

[Qye]

fgets ignores my limit and is trying to read 1024 characters.

char *fgets( char *str, int numChars, FILE *stream );

as I understand fgets it is supposed to read up to numCHars characters from stream into str. It should also stop on a newline

The behavior I see is that changes the numChars in __srefill_r to 1024. I also see no code in the disassembly to deal with \n. By the time _read is called the len argument is 1024. Is stdin a block mode device?

Do I misunderstand fgets or what might be happening here.

I overrode __io_getchar as follows. It is being hit and does return the chars I type. 

int __io_getchar(void)
{
uint8_t ch = '\n';

HAL_StatusTypeDef eStatus;

eStatus = HAL_UART_Receive(&huart3, &ch, 1, HAL_MAX_DELAY);

return ch;
}

[Qye]

I am using this in its place

int getline(char *ptr, int len)

{

    int DataIdx;

    for (DataIdx = 0; DataIdx < len; DataIdx++)

    {

        *ptr = __io_getchar();

        if (*ptr == '\n' )

        {

            *ptr = '\0';

            break;

        }

        ptr++;

    }

    return len;

}

[Qye]

I wrote my own getline since I didnt find it in the libraries