How to read from stdin with fgets()?

Question

I've written the following code to read a line from a terminal window, the problem is the code gets stuck in an infinite loop. The line/sentence is of undefined length, therefore I plan to read it in parts into the buffer, then concatenate it to another string which can be extended via realloc accordingly. Please can somebody spot my mistake or suggest a better way of achieving this?

#include <stdio.h> #include <string.h>  #define BUFFERSIZE 10  int main (int argc, char *argv[]) {     char buffer[BUFFERSIZE];     printf("Enter a message: \n");     while(fgets(buffer, BUFFERSIZE , stdin) != NULL)     {         printf("%s\n", buffer);     }     return 0; } 

Answer 1

here a concatenation solution:

#include <stdio.h> #include <stdlib.h> #include <string.h> #define BUFFERSIZE 10  int main() {   char *text = calloc(1,1), buffer[BUFFERSIZE];   printf("Enter a message: \n");   while( fgets(buffer, BUFFERSIZE , stdin) ) /* break with ^D or ^Z */   {     text = realloc( text, strlen(text)+1+strlen(buffer) );     if( !text ) ... /* error handling */     strcat( text, buffer ); /* note a '\n' is appended here everytime */     printf("%s\n", buffer);   }   printf("\ntext:\n%s",text);   return 0; } 

Answer 2

You have a wrong idea of what fgets returns. Take a look at this: http://www.cplusplus.com/reference/clibrary/cstdio/fgets/

It returns null when it finds an EOF character. Try running the program above and pressing CTRL+D (or whatever combination is your EOF character), and the loop will exit succesfully.

How do you want to detect the end of the input? Newline? Dot (you said sentence xD)?