modifs readme

README.md

@@ -39,14 +39,18 @@
 ## allowed external functions :
 ---
 (extracts of manuals)
+
 **readline :**
+
 - **readline** : `char *readline (const char *prompt);` will read a line from the terminal and return it, using prompt as a prompt
 - **rl_clear_history** : `void rl_clear_history (void)` clear the history list by deleting all of the entries, in the same manner as the History library's clear_history() function
 - **rl_on_new_line** : `int rl_on_new_line (void)` tell the update functions that we have moved onto a new (empty) line, usually after outputting a newline
 - **rl_replace_line** : `void rl_replace_line (const char *text, int clear_undo)` replace the contents of rl_line_buffer with text. The point and mark are preserved, if possible. If clear_undo is non-zero, the undo list associated with the current line is cleared
 - **rl_redisplay** : `void rl_redisplay (void)` change what's displayed on the screen to reflect the current contents of rl_line_buffer
 - **add_history** : `bool readline_add_history (string $prompt)` save the line away in a history list of such lines
+
 **files :**
+
 - **access** : `int access(const char *pathname, int mode);` checks whether the calling process can access the file pathname
 - **open** : `int open(const char *pathname, int flags, [mode_t mode]);` system call opens the file specified by pathname
 - **read** : `ssize_t read(int fd, void *buf, size_t count);` attempts to read up to count bytes from file descriptor fd into the buffer starting at buf
@@ -58,28 +62,38 @@
 - **lstat** : `int fstat(int fd, struct stat *statbuf);` lstat() is  identical  to stat(), except that if pathname is a symbolic link, then it returns information about the link itself, not the file that it refers to
 - **fstat** : `int lstat(const char *pathname, struct stat *statbuf);` fstat() is identical to stat(), except that the file about which information is to be retrieved is specified by the file descriptor fd
 - **unlink** : `int unlink(const char *pathname);` unlink() deletes a name from the filesystem
+
 **process :**
+
 - **fork** : `pid_t fork(void);` creates a new process by duplicating the calling process. The new process is referred to as the child process. The calling process is referred to as the parent process
 - **wait** : `pid_t wait(int *wstatus);` suspends execution of the calling process until one of its children terminates. The call wait(&wstatus) is equivalent to: waitpid(-1, &wstatus, 0);
 - **waitpid** : `pid_t waitpid(pid_t pid, int *wstatus, int options);` suspends execution of the calling process until a child specified by pid argument has changed state
 - **wait3** : `pid_t wait3(int *wstatus, int options, struct rusage *rusage);` obsolete; use waitpid(2). similar to waitpid(2), but additionally return resource usage information about the child in the structure pointed to by rusage
 - **wait4** : `pid_t wait4(pid_t pid, int *wstatus, int options, struct rusage *rusage);` like wait3() but additionally can be used to select a specific child
 - **exit** : `void exit(int status);` causes normal process termination and the value of status & 0377 is returned to the parent (see wait())
+
 **signals :**
+
 - **signal** : `sighandler_t signal(int signum, sighandler_t handler(int));` sets the disposition of the signal signum to handler, which is either SIG_IGN, SIG_DFL, or the address of a  programmer-defined function (a "signal handler")
 - **sigaction** : `int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact);` change the action taken by a process on receipt of a specific signal. 
 - **kill** : `int kill(pid_t pid, int sig);` send any signal to any process group or process
+
 **directories :**
+
 - **getcwd** : `char *getcwd(char *buf, size_t size);` returns a null-terminated string containing an absolute pathname that is the current working directory of the calling process
 - **chdir** : `int chdir(const char *path);` changes the current working directory of the calling process to the directory specified in path
 - **execve** : `int execve(const char *filename, char *const argv[], char *const envp[]);` executes the program pointed to by filename
 - **opendir** : `DIR *opendir(const char *name);` opens a directory stream corresponding to the directory name, and returns a pointer to the directory stream
 - **readdir** : `struct dirent *readdir(DIR *dirp);` returns a pointer to a dirent structure representing the next directory entry in the directory stream pointed to by dirp
 - **closedir** : `int closedir(DIR *dirp);` closes the directory stream associated with dirp
+
 **errors :**
+
 - **strerror** : `char *strerror(int errnum);` returns a pointer to a string that describes the error code passed in the argument errnum
 - **perror** : `void perror(const char *s);` produces a message on standard error describing the last error encountered during a call to a system or library function
+
 **termcap :**
+
 The termcap data base describes the capabilities of hundreds of different display terminals in great detail
 The termcap library is provided for easy access this data base in programs that want to do terminal-independent character-based display output
 
@@ -91,9 +105,12 @@ There are three functions to use to get the value of a capability :
 - **tgetflag** : `int tgetflag (char *name);` get a boolean value
 - **tgetnum** : `int tgetnum (char *name);` get a capability value that is numeric
 - **tgetstr** : `char *tgetstr (char *name, char **area);` get a string value
+
 two more functions :
+
 - **tgoto** : `char *tgoto (char *cstring, int hpos, int vpos)` encoding numeric parameters such as cursor positions into the terminal-specific form required for display commands
 - **tputs** : `int tputs (char *string, int nlines, int (*outfun) ());` output a string containing an optional padding spec
+
 ### other :
 - **printf** : `int printf(const char *format, ...);` produce output to stdout according to a specified format
 - **malloc** : `void *malloc(size_t size);` allocates size bytes and returns a pointer to the allocated memory. The memory is not initialized
@@ -121,6 +138,7 @@ two more functions :
 - [exit code status](https://tldp.org/LDP/abs/html/exitcodes.html)
 - [`char **s` vs `char *s[]`](https://stackoverflow.com/questions/46830654/what-is-the-difference-between-extern-char-environ-and-extern-char-environ)
 - [extern and global](https://stackoverflow.com/questions/2652545/extern-and-global-in-c)
+
 **bash scripts :**
 - [on which stream deos bash redirect its prompt](https://unix.stackexchange.com/questions/20826/which-stream-does-bash-write-its-prompt-to)
 - [fd redirections &](https://putaindecode.io/articles/maitriser-les-redirections-shell)