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| <h4 class="subsection">10.4.4 <code>wordexp</code> Example</h4> |
| |
| <p>Here is an example of using <code>wordexp</code> to expand several strings |
| and use the results to run a shell command. It also shows the use of |
| <code>WRDE_APPEND</code> to concatenate the expansions and of <code>wordfree</code> |
| to free the space allocated by <code>wordexp</code>. |
| |
| <pre class="smallexample"> int |
| expand_and_execute (const char *program, const char **options) |
| { |
| wordexp_t result; |
| pid_t pid |
| int status, i; |
| |
| /* <span class="roman">Expand the string for the program to run.</span> */ |
| switch (wordexp (program, &result, 0)) |
| { |
| case 0: /* <span class="roman">Successful</span>. */ |
| break; |
| case WRDE_NOSPACE: |
| /* <span class="roman">If the error was </span><code>WRDE_NOSPACE</code><span class="roman">,</span> |
| <span class="roman">then perhaps part of the result was allocated.</span> */ |
| wordfree (&result); |
| default: /* <span class="roman">Some other error.</span> */ |
| return -1; |
| } |
| |
| /* <span class="roman">Expand the strings specified for the arguments.</span> */ |
| for (i = 0; options[i] != NULL; i++) |
| { |
| if (wordexp (options[i], &result, WRDE_APPEND)) |
| { |
| wordfree (&result); |
| return -1; |
| } |
| } |
| |
| pid = fork (); |
| if (pid == 0) |
| { |
| /* <span class="roman">This is the child process. Execute the command.</span> */ |
| execv (result.we_wordv[0], result.we_wordv); |
| exit (EXIT_FAILURE); |
| } |
| else if (pid < 0) |
| /* <span class="roman">The fork failed. Report failure.</span> */ |
| status = -1; |
| else |
| /* <span class="roman">This is the parent process. Wait for the child to complete.</span> */ |
| if (waitpid (pid, &status, 0) != pid) |
| status = -1; |
| |
| wordfree (&result); |
| return status; |
| } |
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