Introduction

21.1. Introduction#

The kernel character input/output support is an extension of the I/O Manager to output characters to the kernel character output device and receive characters from the kernel character input device using a polled and non-blocking implementation.

The directives may be used to print debug and test information. The kernel character input/output support should work even if no Console Driver is configured, see CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER. The kernel character input and output device is provided by the BSP. Applications may change the device. The directives provided by the Kernel Character I/O Support are:

  • rtems_putc() - Outputs the character to the kernel character output device.

  • rtems_put_char() - Puts the character using rtems_putc()

  • putk() - Outputs the characters of the string and a newline character to the kernel character output device.

  • printk() - Outputs the characters defined by the format string and the arguments to the kernel character output device.

  • vprintk() - Outputs the characters defined by the format string and the variable argument list to the kernel character output device.

  • rtems_printk_printer() - Outputs the characters defined by the format string and the variable argument list to the kernel character output device.

  • getchark() - Tries to dequeue a character from the kernel character input device.