[NTLUG:Discuss] C pointer questions

[Fred James]

What I am trying to do is append one body of text to another (B to A), 
both of which are referenced by pointers, and then copy A to B so the 
result would be the same as if I had inserted A at the top of B (because 
I am going to use B in my final fwrite()).  Any suggestions would be 
most apprecated.  Full code upon request.

Here is a snippet of the orginal C code, which works by the way:
[original code begins]
     sprintf(mailCmd,
             "/usr/sbin/mailx -s '%s' %s",
             pSubject,
             pRecipientList);

     errno = 0;

     if ( (pMailPipe = popen (mailCmd, "w")) != NULL )
     {
         if ( fwrite (pMessage, strlen (pMessage), 1, pMailPipe)
              == strlen (pMessage) )
         {
             errorStatus = pclose(pMailPipe);
         }
         else
         {
             errorStatus = errno;
             (void) pclose (pMailPipe);
         }
     }
     else
     {
         errorStatus = errno;
     }

     return errorStatus;
[original code ends]

Here is the same snippet plus some stuff I am trying to add (at the 
top), without too much success so far:
[modified code begins]
     sprintf(AppendCmd, "echo \"~|uuencode '%s'\" > '%s'", pAttachment, 
pAttachment);
	system(AppendCmd);
     sprintf(AppendCmd, "cat '%s' >> '%s'", pMessage, pAttachment);
	system(AppendCmd);
	pMessage = pAttachment;

     sprintf(mailCmd,
             "/usr/sbin/mailx -s '%s' %s",
             pSubject,
             pRecipientList);

     errno = 0;

     if ( (pMailPipe = popen (mailCmd, "w")) != NULL )
     {
         if ( fwrite (pMessage, strlen (pMessage), 1, pMailPipe)
              == strlen (pMessage) )
         {
             errorStatus = pclose(pMailPipe);
         }
         else
         {
             errorStatus = errno;
             (void) pclose (pMailPipe);
         }
     }
     else
     {
         errorStatus = errno;
     }

     return errorStatus;
}
[modified code ends]


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