Thread: gcc and gets

hey.
when I use gcc to compile my .c-files it complains about the gets library function and says that "it is dangerous and should not be used". anyone know why?

dagH

anyone know why?

Because it's dangerous and shouldn't be used? gets() doesn't allow you to stop reading when the array is full, so can end up writing past the end if the array and breaking all kinds of things. Use fgets() instead because it lets you pass a limit to the number of characters it can read.

by using gets() you risk having characters left in the input stream (stdin), usually new lines after you've taken what you've asked for out.

gets() doesn't have that problem at all. It always reads a full line, including the '\n'.

Unless it's read but not included...?

You get a gold star. gets() removes the '\n' from the stream but doesn't store it in the array. The standard tells you that, but you can also test it with a quick program:

Code:

#include <stdio.h>


int main( void ) {
  char s[BUFSIZ];

  gets( s );
  puts( "Done with gets()" );
  getchar();
  puts( "Done with getchar()" );

  return 0;
}

The getchar() call will block because there's nothing in the stream to read, not even a '\n'.

Originally Posted by daghenningsorbo

hey.
when I use gcc to compile my .c-files it complains about the gets library function and says that "it is dangerous and should not be used". anyone know why?

dagH

gcc has nothing to do with it. It is the LINKER which complains. And you should heed the warning.