How to read from stdin in NIOSII with the small_c_library

Hi,

Are you saying that, using normal c libraries you are able to read write but not able to read using small c libraries ?

1. If simple console read write ->use alt_printf, alt_putstr, alt_putchar & alt_getchar. Refer table 34 gives you the comparison between libraries https://www.intel.com/content/altera-www/global/en_us/index/documentation/mwh1416947091611.html#mwh1416946791328__ID-356-000027c6 OR
2. If Read, write to from FPGA peripherals? use IORD and IOWR functions.

Let me know if this has helped resolve the issue you are facing or if you need any further assistance.

Best Regards,

Anand

Yes, i am able to read incoming data (from the uart) with the full C library, using:

#include <stdio.h>
#include <stdlib.h>
 
FILE * fp;
 
char msg[255];
fp = fopen("/dev/uart_0","r");
		if(fp)
		{
			fscanf(fp,"%s",msg);
                  }

I've tried using the alt library, but it fails with:

home/user/project_name/software/nios_project_name_bsp/HAL/src/alt_getchar.c:67: undefined reference to `getc'

//source snippet
int 
alt_getchar(void)
{
#ifdef ALT_SEMIHOSTING
    char c;
    read(STDIN_FILENO,&c,1);
    return c;
#else
#ifdef ALT_USE_DIRECT_DRIVERS
    ALT_DRIVER_READ_EXTERNS(ALT_STDIN_DEV);
    char c;
 
    if (ALT_DRIVER_READ(ALT_STDIN_DEV, &c, 1, alt_fd_list[STDIN_FILENO].fd_flags) <= 0) {
        return -1;
    }
    return c;
#else
    return getchar();
#endif
#endif
}

It seems that the direct device drivers aren't available, and neither is getc.

is it some header missing or something similar?