#define _POSIX_C_SOURCE 200809L
#include <stdio.h>
#include <stdlib.h>

int main()
{
	enum{MAXSTRLEN=50000};

	FILE *f = popen("uname -a","r");
	if(!f)
		return 1;
	char *string = calloc(MAXSTRLEN+1,1);	
	size_t n=fread(string,1,MAXSTRLEN,f);
	if(!ferror(f))
		printf("%zu Zeichen gelesen: %s",n,string);
	fclose(f);
	free(string);
	return 0;
}