popen equivalent in c++
You can use the “not yet official” boost.process if you want an object-oriented approach for managing the subprocess. Or you can just use popen itself, if you don’t mind the C-ness of it all.
popen
What is the subprocess.Popen max length of the args parameter?
If you’re passing shell=False, then Cmd.exe does not come into play. On windows, subprocess will use the CreateProcess function from Win32 API to create the new process. The documentation for this function states that the second argument (which is build by subprocess.list2cmdline) has a max length of 32,768 characters, including the Unicode terminating null character. … Read more
subprocess.Popen in different console
To open in a different console, do (tested on Win7 / Python 3): from subprocess import Popen, CREATE_NEW_CONSOLE Popen(‘cmd’, creationflags=CREATE_NEW_CONSOLE) input(‘Enter to exit from Python script…’) Related How can I spawn new shells to run python scripts from a base python script?
Opening a process with Popen and getting the PID
From the documentation at http://docs.python.org/library/subprocess.html: Popen.pid The process ID of the child process. Note that if you set the shell argument to True, this is the process ID of the spawned shell. If shell is false, it should behave as you expect, I think. If you were relying on shell being True for resolving executable … Read more
subprocess.Popen() IO redirect
Altenatively, you can use the stdout parameter with a file object: with open(‘temp.txt’, ‘w’) as output: server = subprocess.Popen(‘./server.py’, stdout=output) server.communicate() As explained in the documentation: stdin, stdout and stderr specify the executed program’s standard input, standard output and standard error file handles, respectively. Valid values are PIPE, an existing file descriptor (a positive integer), … Read more
subprocess.wait() not waiting for Popen process to finish (when using threads)?
You could also use check_call() instead of Popen. check_call() waits for the command to finish, even when shell=True and then returns the exit code of the job.
How to do multiple arguments with Python Popen?
To directly answer your question, read below. But there’s a lot of problems with your program, some of which I cover in “Better practice.” By default, subprocess.Popen commands are supplied as a list of strings. However, you can also you can use the shell argument to execute a command “formatted exactly as it would be … Read more
How to prevent fgets blocks when file stream has no new data
In Linux (or any Unix-y OS), you can mark the underlying file descriptor used by popen() to be non-blocking. #include <fcntl.h> FILE *proc = popen(“tail -f /tmp/test.txt”, “r”); int fd = fileno(proc); int flags; flags = fcntl(fd, F_GETFL, 0); flags |= O_NONBLOCK; fcntl(fd, F_SETFL, flags); If there is no input available, fgets will return NULL … Read more
Why does subprocess.Popen() with shell=True work differently on Linux vs Windows?
Actually on Windows, it does use cmd.exe when shell=True – it prepends cmd.exe /c (it actually looks up the COMSPEC environment variable but defaults to cmd.exe if not present) to the shell arguments. (On Windows 95/98 it uses the intermediate w9xpopen program to actually launch the command). So the strange implementation is actually the UNIX … Read more
Bash style process substitution with Python’s Popen
If pram_axdnull understands “-” convention to mean: “read from stdin” then you could: p = Popen([“pram_axdnull”, str(kmer), input_filename, “-“], stdin=PIPE, stdout=PIPE) output = p.communicate(generate_kmers(3))[0] If the input is generated by external process: kmer_proc = Popen([“generate_kmers”, str(kmer)], stdout=PIPE) p = Popen([“pram_axdnull”, str(kmer), input_filename, “-“], stdin=kmer_proc.stdout, stdout=PIPE) kmer_proc.stdout.close() output = p.communicate()[0] If pram_axdnull doesn’t understand “-” convention: … Read more