BDD P. Système P. Linéaire POO G. Logiciel Simu Anglais

L3

Sujet

Écrire un programme en C qui crée deux processus communiquant par tube. Le processus fils lit sur l'entrée standard et le processus père affiche ce qui a été lu sur l'entrée standard en remplaçant les majuscules par des minuscules.

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>


#define MAX 64

char majmin(char c) {
  if (c >= 'A' && c <= 'Z') {
    return c + ('a' - 'A');
  } else {
    return c;
  }
}

/**                          Tube
 *             T[1]  |===================| T[0]
 *              |                            |
 *              |                            |
 *    +-----|Tampon|                      |Tampon|
 *    |                                      +---------|
 * +-----+                                             +
 * |-|-|-| <------- Clavier           Écran --------> |o|
 * +-----+
 *
 *  fils                                     père
 */
int main() {
  int pid, T[2], n, i, status;
  char tampon[MAX];

if (pipe(T) == -1) {
    perror("Erreur de pipe");
    exit(1);
  }

pid = fork();

if (pid < 0) {
    perror("Erreur lors de la creation du processus");
    exit(1);
  }

if (pid == 0) {
    close(T[0]);
<span class="k">while</span> <span class="p">((</span><span class="n">n</span> <span class="o">=</span> <span class="n">read</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="n">tampon</span><span class="p">,</span> <span class="n">MAX</span><span class="p">)))</span>
  <span class="n">write</span><span class="p">(</span><span class="n">T</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="n">tampon</span><span class="p">,</span> <span class="n">n</span><span class="p">);</span>

} else {
    close(T[1]);
<span class="k">while</span> <span class="p">((</span><span class="n">n</span> <span class="o">=</span> <span class="n">read</span><span class="p">(</span><span class="n">T</span><span class="p">[</span><span class="mi">0</span><span class="p">],</span> <span class="n">tampon</span><span class="p">,</span> <span class="n">MAX</span><span class="p">)))</span> <span class="p">{</span>
  <span class="k">for</span> <span class="p">(</span><span class="n">i</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> <span class="n">i</span> <span class="o">&lt;</span> <span class="n">n</span><span class="p">;</span> <span class="n">i</span><span class="o">++</span><span class="p">)</span>
    <span class="n">tampon</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="n">majmin</span><span class="p">(</span><span class="n">tampon</span><span class="p">[</span><span class="n">i</span><span class="p">]);</span>

  <span class="n">write</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">tampon</span><span class="p">,</span> <span class="n">n</span><span class="p">);</span>

  <span class="c1">// Simplement utilisé pour récupérer le code retour</span>
  <span class="c1">// de l'exécution du processus fils.</span>
  <span class="n">wait</span><span class="p">(</span><span class="o">&amp;</span><span class="n">status</span><span class="p">);</span>
<span class="p">}</span>

<span class="n">close</span><span class="p">(</span><span class="n">T</span><span class="p">[</span><span class="mi">0</span><span class="p">]);</span>

}
}