os_cp:fork_exec_pipes
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os_cp:fork_exec_pipes [2025/05/19 22:27] jkonczak |
os_cp:fork_exec_pipes [2026/05/20 20:31] (current) jkonczak |
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| There is a list of things that ''fork'' does not clone or that are reset for the | There is a list of things that ''fork'' does not clone or that are reset for the | ||
| - | child process upon ''fork''. See POSIX standard or Linux manual on fork for details. | + | child process upon ''fork''. |
| + | \\ See POSIX standard or | ||
| + | [[https://man7.org/linux/man-pages/man2/fork.2.html|Linux manual on fork]] | ||
| + | for details. | ||
| + | \\ | ||
| Notice that: | Notice that: | ||
| * all stack and heap memory is copied | * all stack and heap memory is copied | ||
| Line 160: | Line 164: | ||
| <html><div style="margin-bottom:-1.4em"></div></html> | <html><div style="margin-bottom:-1.4em"></div></html> | ||
| <code c> | <code c> | ||
| - | char arg0[] = "ls"; char arg2[] = "-a"; | ||
| - | char arg1[] = "-l"; char arg3[] = "/tmp"; | ||
| - | char *argv[] = {arg0, arg1, arg2, arg3, NULL}; | ||
| # Argument list: | # Argument list: | ||
| - | execlp("ls", arg0, arg1, arg2, arg3, NULL); | + | execlp("ls", "ls", "-l", "-a", "/tmp", NULL); |
| - | # Argument vector: | + | |
| + | # Argument vector: | ||
| + | char *argv[] = {"ls", "-l", "-a", "/tmp", NULL}; | ||
| execvp("ls", argv); | execvp("ls", argv); | ||
| </code> | </code> | ||
| Line 233: | Line 236: | ||
| double elapsedSec = (end.tv_sec - start.tv_sec) + (end.tv_nsec - start.tv_nsec) / 1e9; | double elapsedSec = (end.tv_sec - start.tv_sec) + (end.tv_nsec - start.tv_nsec) / 1e9; | ||
| </code> | </code> | ||
| + | <HTML></div><div style="margin-top:-1.4em"></HTML> | ||
| + | Instead of the C11 function ''[[https://en.cppreference.com/c/chrono/timespec_get|timespec_get]](&//x//, TIME_UTC);'', you may also | ||
| + | use the POSIX function ''[[https://pubs.opengroup.org/onlinepubs/9799919799/functions/clock_gettime.html|clock_gettime]](CLOCK_MONOTONIC, &//x//);''. | ||
| <HTML></div></HTML> | <HTML></div></HTML> | ||
| </small> | </small> | ||
| Line 387: | Line 393: | ||
| <small>Pipe is unidirectional. The unix //socket// is its bidirectional | <small>Pipe is unidirectional. The unix //socket// is its bidirectional | ||
| equivalent. See ''[[https://man7.org/linux/man-pages/man7/unix.7.html|man 7 unix]]'' | equivalent. See ''[[https://man7.org/linux/man-pages/man7/unix.7.html|man 7 unix]]'' | ||
| - | for details.</small> | + | for details. |
| + | \\ | ||
| + | POSIX standard also defines (but not mandates) | ||
| + | [[https://man7.org/linux/man-pages/man7/mq_overview.7.html|message queues]]. | ||
| + | </small> | ||
| ~~Exercise.#~~ Write a program that: | ~~Exercise.#~~ Write a program that: | ||
os_cp/fork_exec_pipes.txt · Last modified: 2026/05/20 20:31 by jkonczak
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