stdin

问题 How can I intercept Ctrl + C (which normally would kill the process) in a CLI (command line interface) Java application? Does a multi-platform solution exist (Linux, Solaris, Windows)? I\'m using Console \'s readLine() , but if necessary, I could use some other method to read characters from standard input. 回答1: Runtime.getRuntime().addShutdownHook(new Thread() { public void run() { /* my shutdown code here */ } }); This should be able to intercept the signal, but only as an intermediate step

问题 When I execute \" python \" from the terminal with no arguments it brings up the Python interactive shell. When I execute \" cat | python \" from the terminal it doesn\'t launch the interactive mode. Somehow, without getting any input, it has detected that it is connected to a pipe. How would I do a similar detection in C or C++ or Qt? 回答1: Use isatty : #include <stdio.h> #include <io.h> ... if (isatty(fileno(stdin))) printf( "stdin is a terminal\n" ); else printf( "stdin is a file or a pipe

问题 What is the simplest way to read a full line in a C console program The text entered might have a variable length and we can\'t make any assumption about its content. 回答1: You need dynamic memory management, and use the fgets function to read your line. However, there seems to be no way to see how many characters it read. So you use fgetc: char * getline(void) { char * line = malloc(100), * linep = line; size_t lenmax = 100, len = lenmax; int c; if(line == NULL) return NULL; for(;;) { c =

问题 How to flush the stdin ?? Why is it not working in the following code snippet? #include <string.h> #include <stdio.h> #include <malloc.h> #include <fcntl.h> int main() { int i=0,j=0, sat; char arg[256]; char * argq; argq = malloc(sizeof(char)*10); printf(\"Input the line\\n\"); i=read(0, arg, sizeof(char)*9); arg[i-1]=\'\\0\'; fflush(stdin); i=read(0, argq, sizeof(char)*5); argq[i-1]=\'\\0\'; puts(arg); puts(argq); return 0; } Now if i give the input as 11 characters, only 9 should be read

问题 I\'m trying to do the opposite of \"Detect if stdin is a terminal or pipe?\". I\'m running an application that\'s changing its output format because it detects a pipe on STDOUT, and I want it to think that it\'s an interactive terminal so that I get the same output when redirecting. I was thinking that wrapping it in an expect script or using a proc_open() in PHP would do it, but it doesn\'t. Any ideas out there? 回答1: Aha! The script command does what we want... script --return --quiet -c "

问题 If I do the following: import subprocess from cStringIO import StringIO subprocess.Popen([\'grep\',\'f\'],stdout=subprocess.PIPE,stdin=StringIO(\'one\\ntwo\\nthree\\nfour\\nfive\\nsix\\n\')).communicate()[0] I get: Traceback (most recent call last): File \"<stdin>\", line 1, in ? File \"/build/toolchain/mac32/python-2.4.3/lib/python2.4/subprocess.py\", line 533, in __init__ (p2cread, p2cwrite, File \"/build/toolchain/mac32/python-2.4.3/lib/python2.4/subprocess.py\", line 830, in _get_handles

问题 I want to read the name entered by my user using C programmes. For this I wrote: char name[20]; printf(\"Enter name: \"); gets(name); But using gets is not good, so what is a better way? 回答1: You should never use gets (or scanf with an unbounded string size) since that opens you up to buffer overflows. Use the fgets with a stdin handle since it allows you to limit the data that will be placed in your buffer. Here's a little snippet I use for line input from the user: #include <stdio.h>

问题 I\'m trying to do some of the code golf challenges, but they all require the input to be taken from stdin . How do I get that in Python? 回答1: You could use the fileinput module: import fileinput for line in fileinput.input(): pass fileinput will loop through all the lines in the input specified as file names given in command-line arguments, or the standard input if no arguments are provided. Note: line will contain a trailing newline; to remove it use line.rstrip() 回答2: There's a few ways to

问题 So a quick Google search for fflush(stdin) for clearing the input buffer reveals numerous websites warning against using it. And yet that\'s exactly how my CS professor taught the class to do it. How bad is using fflush(stdin) ? Should I really abstain from using it, even though my professor is using it and it seems to work flawlessly? 回答1: Simple: this is undefined behavior, since fflush is meant to be called on an output stream. This is an excerpt from the C standard: int fflush(FILE