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--- os_cp:pipes_signals [2023/04/18 21:50] – utworzono jkonczak
+++ os_cp:pipes_signals [2023/05/09 21:18] (current) – [Shared memory] jkonczak
@@ Line 120: / Line 120: @@
 \\
 <small> You may do this e.g., by: ''pipe'', ''fork'', in one process: ''dup2''
-and ''exec'', in the other process: reading from pipe and changing case.</small>
+and ''exec'', in the other process: reading from pipe and changing case.
+\\
+The ''[[https://en.cppreference.com/w/c/string/byte/toupper|toupper]]'' function (available from ''ctype.h'') converts a single character to upper case.
-~~Exercise.#~~ Write a program that does ''ps -eF | sort -nk6''.
+~~Exercise.#~~ Write a program that does ''ps -eF | sort -nk6''.</small>
 ===== Signals =====
-Disclaimer: these materials contain the very basics signals.
+Disclaimer: these materials contain the very basics of signals.
-For a comprehensive information on signals, see the
+For comprehensive informations, see the
 [[https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04|POSIX standard]].
@@ Line 428: / Line 430: @@
 To ensure that the file is large enough, one can use the following functions:
   * ''[[https://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html|ftruncate]]'' <html><span style="float:right"><small>Needs header: <code>unistd.h</code></small></span></html> resizes file to a given size. \\ Whenever the file is larger it is truncated.
-  * ''[[https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_fallocate.html|posix_fallocate]]'' <html><span style="float:right"><small>Needs header: <code>fcntl.h</code></small></span></html> ensures that the file at least of a given size. \\ Whenever the file is larger it is left unchanged. \\ <small>Warning: ''posix_fallocate'' is guaranteed to work for ordinary files. Result of using ''posix_fallocate'' on shared memory object is undefined.</small>
+  * ''[[https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_fallocate.html|posix_fallocate]]'' <html><span style="float:right"><small>Needs header: <code>fcntl.h</code></small></span></html> ensures that the file at least of a given size. \\ Whenever the file is larger it is left unchanged. \\ <small>Warning: ''posix_fallocate'' is guaranteed to work for ordinary files. The result of using ''posix_fallocate'' on a shared memory object is undefined.</small>
 To clean up the memory mapping, one has to use the
@@ Line 441: / Line 443: @@
 <html><p style="text-align: center"><object id="svg-object" data="/jkonczak/_media/os_cp:mmap.svg" type="image/svg+xml"></object></p></html>
+**To compile programs that use ''shm_open'' with older glibc versions, one must add ''-lrt'' to compile options.**
 ~~Exercise.#~~
@@ Line 497: / Line 501: @@
     char c, text[1022] = {0};
-    scanf("%[^\n]1021", text);
+    scanf("%1021[^\n]", text);
     do { // this reads all remaining characters in this line including '\n'
       c = getchar();
@@ Line 575: / Line 579: @@
 }
 </code>
-//one must use msync()
-//to sync data to disk
 ~~META: