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copied!<ol> <li>Yes, it is. There's no specific violations of the standard there. The <code>memset</code> is a waste of time however since it's al going to be overwritten anyway (make your first <code>strcat</code> into a <code>strcpy</code>). And you should <em>always</em> check for <code>malloc</code> returning NULL. <em>No matter what!</em></li> <li>C89/90 is not the current standard, C99 is. And C1x is not that far away. GCC is keeping up with the bleeding edge.</li> <li>Only use local arrays if you don't need them to survive beyond the end of the function. Otherwise <code>malloc</code> is your best bet, particularly if you want to <em>return</em> the combined string.</li> <li>I think gcc has the <code>-std=c89</code> flag or something similar. In any case, MSVC does not always follow the standard :-)</li> <li>Compile and test it on both platforms frequently. That's the only way to be sure.</li> </ol> <p>I would opt for:</p> <pre><code>void foo (const char *p1, const char *p2, const char *p3) { size_t length = strlen(p1) + strlen(p2) + strlen(p3); char *combined = (char *) malloc(length + 1); if (combined == NULL) { printf("Result : <unknown since I could't get any memory>\n"); } else { strcpy(combined, p1); strcat(combined, p2); strcat(combined, p3); printf("Result : %s", combined); free(combined); } } </code></pre> <p>or, since you're not actually doing anything with the string except printing it:</p> <pre><code>void foo (const char *p1, const char *p2, const char *p3) { printf("Result : %s%s%s", p1, p2, p3); } </code></pre> <p>:-)</p> <p>Another strategy I've seen is the "only allocate if you have to" strategy:</p> <pre><code>void foo (const char *p1, const char *p2, const char *p3) { char str1k[1024]; char *combined; size_t length = strlen (p1) + strlen (p2) + strlen (p3) + 1; if (length <= sizeof(str1k)) combined = str1k; else combined = malloc (length); if (combined == NULL) { printf ("Result : <unknown since I couldn't get any memory>\n"); } else { strcpy (combined, p1); strcat (combined, p2); strcat (combined, p3); printf ("Result : %s", combined); } if (combined != str1k) free (combined); } </code></pre> <p>which uses stack storage if the combined string will fit and only allocates memory if it won't. This can often lead to a substantial speed improvement if the bulk of strings combine into less than the limit.</p>

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