When an invalid character is entered the code goes into an endless loop. It seems this line:
Is essentially the same as this:
It may check the condition, but in this case that condition will never change. You could that same check in an if statement so it is only checked once. Or use the while(1) in that loop with breaks to jump out of the loop when needed. You might want to look into fgets. The scanf function is great for learning, but can introduce potential security problems. Hope that helps.
hi,
how does a program know whether some data are available from stdin?
I would like to make a program which could read its data from stdin
and _if_there_is_nothing_at_stdin_ from a file which name is given
as an argument. If there is nothing in stdin and no filename is given as
argument,... (2 Replies)
hello all,
I need to create a password change utility for a database. I need to gather at the command line the username, password and database sid. I have the program currently doing this. What I would like to do is not have the new password appear on the screen when I do my read command.... (2 Replies)
Howdie everyone...
I have a shell script RemoveFiles.sh
Inside this file, it only has two commands as below:
rm -f ../../reportToday/temp/*
rm -f ../../report/*
My problem is that when i execute this script, nothing happened. Files remained unremoved. I don't see any error message as it... (2 Replies)
can you redirect STDIN with command arguments?
I have tried this approach:
# ./script -option <argument1> <argument2> 0<$2
# $2: ambiguous redirect
Is this possible? (4 Replies)
Hi,
Program A: uses pipe()
I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using:
* child
-> dup2(fd, STDOUT_FILENO);
-> execl("/path/PROGRAM B", "PROGRAM B", NULL);
* parent
-> char line;
-> read(fd, line, 100);
Question:
---------... (1 Reply)
Hi,
Program A: uses pipe()
I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using:
* child
-> dup2(fd, STDOUT_FILENO);
-> execl("/path/PROGRAM B", "PROGRAM B", NULL);
* parent
-> char line;
-> read(fd, line, 100);
Question:
---------... (3 Replies)
When a process fork(), the child share the same file descriptors as his father. Thus, they share the same stdin. Quick and dirty exemple below (sorry for the ugly gets() call) :
#include <stdio.h>
#include <unistd.h>
int main()
{
char buf;
if (fork()) { /*parent */
... (1 Reply)
Bonjour,
Mon application en C sous linux tourne en redirigeant stdin vers un fichier.
Exemple; $appli1 <file1.
PB: Je voudrais temporairement redonner la main au user sur le clavier.
Alors je pensais ajouter system("appli2"); dans appli1.
Dans son main() , appli2() fait seulement un... (1 Reply)
Hi,
I has the following command in the script. This command works fine if I execute on command prompt. If I run the script, this is not working as expected (deleting CR).
tr -d "\015" < ${FilePath}/${FileName} > ${FilePath}/${File_Prefix}.csv
I could not figure out whats... (6 Replies)
hi all. and sorry for the random question, but this sparkled a raging flame-war at work and i want more points of view
situation
a router, with linux of some sort,
dhcp client requesting for ip in wan1 (as usual with wan ports)
dhcp server listening in lan1, and assigning ip (as usual... (9 Replies)
Discussion started by: broli
9 Replies
LEARN ABOUT HPUX
pthread_cond_broadcast
pthread_cond_signal(3T)pthread_cond_signal(3T)NAME
pthread_cond_signal(), pthread_cond_broadcast() - unblock one or all threads waiting on a condition variable
SYNOPSIS PARAMETERS
cond Pointer to the condition variable to be signaled or broadcast.
DESCRIPTION
The function is used to wake-up one of the threads that are waiting for the occurrence of a condition associated with condition variable
cond. If there are no threads blocked on cond, this function has no effect. If more than one thread is blocked on cond, the scheduling
policy determines which thread is unblocked. It is possible that more than one thread can be unblocked due to a spurious wakeup.
The function is used to wake-up all threads that are waiting for the occurrence of a condition associated with the condition variable cond.
If there are no threads blocked on cond, this function has no effect. If more than one thread is blocked on cond, the scheduling policy
determines the order in which threads are unblocked.
The condition variabled denoted by cond must have been dynamically initialized by a call to or statically initialized with the macro
An unblocked thread will reacquire the mutex it held when it started the condition wait before returning from or The threads that are
unblocked contend for the mutex according to their scheduling policy and priority.
The or functions can be called by a thread whether or not it currently owns the condition variable's associated mutex. For predictable
scheduling behavior and to prevent lost wake-ups, the mutex should be held when signaling a condition variable.
Usage
When using condition variables, there is a boolean predicate associated with each condition wait. If this predicate is false, the thread
should do a condition wait. Spurious wakeups may occur when waiting on a condition variable. Because the return values from and do not
imply anything about the value of this predicate, the predicate should always be re-evaluated.
Applications using condition variables typically acquire a mutex and enter a loop which checks the predicate. Depending on the value of
the predicate, the thread either breaks out of the loop or waits on the condition. On return from the condition wait, the predicate is re-
evaluated.
RETURN VALUE
Upon successful completion, and return zero. Otherwise, an error number is returned to indicate the error (the variable is not set).
ERRORS
For each of the following conditions, if the condition is detected, the and functions return the corresponding error number:
[EINVAL] cond is not a valid condition variable.
[EFAULT] cond parameter points to an illegal address.
AUTHOR
and were derived from the IEEE POSIX P1003.1c standard.
SEE ALSO pthread_cond_init(3T), pthread_cond_wait(3T).
STANDARDS CONFORMANCE
Pthread Library pthread_cond_signal(3T)