Xilinx SDK: Stop getchar() from waiting for RETURN

I often want to read a single character from the UART or stdin. By default getchar() buffers all input until a RETURN character occurs.

Here are two ways to handle this:

• You can turn off the buffering on the stdin stream:

  setvbuf(stdin, NULL, _IONBF, 0);
  int c = getchar();
  

• Or you just don’t use getchar() at all. Use inbyte() instead (this is what getchar() does anyway):

  #include "xuartps_hw.h"
  
  char c = inbyte();
  

• You can use XUartPs_IsReceiveData() to check if a character is available before you call inbyte() :

  #include "xuartps_hw.h"
  
  if (XUartPs_IsReceiveData(STDIN_BASEADDRESS)) {
      char c = inbyte();
  }