Correzioni alla citazione del codice

diff --git a/ipc.tex b/ipc.tex
index 9d537d479eb615c123d3b3394b168f9058aa2aaa..536d0960ce3a5c81630a339dc56c8f771f7ed484 100644 (file)
--- a/ipc.tex
+++ b/ipc.tex
@@ -184,7 +184,7 @@ nel file \file{BarCodePage.c} che si trova nella directory dei sorgenti.
 int main(int argc, char *argv[], char *envp[])
 {
     ...
-    /* create two pipes to handle process communication */
+    /* create two pipes, pipein and pipeout, to handle communication */
     if ( (retval = pipe(pipein)) ) {
         WriteMess("input pipe creation error");
         exit(0);        
@@ -204,14 +204,14 @@ int main(int argc, char *argv[], char *envp[])
         dup2(pipein[0], STDIN_FILENO);   /* remap stdin to pipe read end */
         close(pipeout[0]);
         dup2(pipeout[1], STDOUT_FILENO); /* remap stdout in pipe output */
-        execlp("barcode", "barcode", size, NULL); //"-o", "-",  NULL);
+        execlp("barcode", "barcode", size, NULL);
     } 
     close(pipein[0]);                    /* close input side of input pipe */
     write(pipein[1], argv[1], strlen(argv[1]));  /* write parameter to pipe */
     close(pipein[1]);                    /* closing write end */
     waitpid(pid, NULL, 0);               /* wait child completion */
     /* Second fork: use child to run ghostscript */
-    if ( (pid = fork()) == -1) {          /* on error exit */
+    if ( (pid = fork()) == -1) {
         WriteMess("child creation error");
         exit(0);
     }
@@ -240,7 +240,7 @@ La prima operazione del programma (\texttt{\small 4--12}) 
 le due pipe che serviranno per la comunicazione fra i due comandi utilizzati
 per produrre il codice a barre; si ha cura di controllare la riuscita della
 chiamata, inviando in caso di errore un messaggio invece dell'immagine
-richiesta.\footnote{la funzione \func{WriteMess}, non è riportata in
+richiesta.\footnote{la funzione \func{WriteMess} non è riportata in
   \secref{fig:ipc_barcodepage_code}; essa si incarica semplicemente di
   formattare l'uscita alla maniera dei CGI, aggiungendo l'opportuno
   \textit{mime type}, e formattando il messaggio in HTML, in modo che

diff --git a/sources/BarCodePage.c b/sources/BarCodePage.c
index ef48ce77bcd4d2d6c2fb43e7e9673d47b935fc08..419e9c0e1898ae9dacd460716dba303d9f70ce4d 100644 (file)
--- a/sources/BarCodePage.c
+++ b/sources/BarCodePage.c
@@ -1,4 +1,4 @@
-/* BarCodeOld.c
+/* BarCodePage.c
  * 
  * Copyright (C) 2002 Simone Piccardi
  * 
@@ -29,7 +29,7 @@
  * http://localhost/cgi-bin/barcode?string
  * where string is the code to be converted
  *
- * $Id: BarCodePage.c,v 1.1 2002/06/30 13:26:17 piccardi Exp $ 
+ * $Id: BarCodePage.c,v 1.2 2002/08/10 14:22:53 piccardi Exp $ 
  *
  ****************************************************************/
 /* 
@@ -38,7 +38,6 @@
 #include <sys/types.h>   /* predefined types */
 #include <sys/stat.h>    /* stat deinitiions */
 #include <unistd.h>      /* include unix standard library */
-/* */
 #include <stdio.h>      /* include standard I/O library */
 #include <stdlib.h>     /* include standard library */
 #include <string.h>     /* include string library */
@@ -50,7 +49,6 @@
 #include"macros.h"
 void WriteMess(char *mess);
 
-
 /* Program begin */
 int main(int argc, char *argv[], char *envp[])
 {
@@ -66,7 +64,7 @@ int main(int argc, char *argv[], char *envp[])
     /* 
      * Begin
      */
-    /* create two pipes to handle process communication */
+    /* create two pipes, pipein and pipeout, to handle communication */
     if ( (retval = pipe(pipein)) ) {
        WriteMess("input pipe creation error");
        exit(0);        
@@ -75,11 +73,10 @@ int main(int argc, char *argv[], char *envp[])
        WriteMess("output pipe creation error");
        exit(0);        
     }   
-    /* fork child to run barcode program */
-    pid = fork();
-    if (pid == -1) {
+    /* First fork: use child to run barcode program */
+    if ( (pid = fork()) == -1 ) {
        WriteMess("child creation error");
-       exit(0);        
+       exit(0);
     }
     /* if child */
     if (pid == 0) {
@@ -92,7 +89,7 @@ int main(int argc, char *argv[], char *envp[])
        dup2(pipein[0], STDIN_FILENO);   /* remap stdin in pipe input */
        close(pipeout[0]);
        dup2(pipeout[1], STDOUT_FILENO); /* remap stdout in pipe output */
-       execlp("barcode", "barcode", size, NULL); //"-o", "-",  NULL);
+       execlp("barcode", "barcode", size, NULL); 
     } 
     /*
      * Parent write string to pipe input and close it, 
@@ -103,9 +100,8 @@ int main(int argc, char *argv[], char *envp[])
     write(pipein[1], argv[1], strlen(argv[1]));
     close(pipein[1]);
     waitpid(pid, NULL, 0);
-    /* Second fork use child to run ghostscript*/
-    pid = fork();
-    if (pid == -1) {
+    /* Second fork: use child to run ghostscript*/
+    if ( (pid = fork()) == -1) {
        WriteMess("child creation error");
        exit(0);
     }