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Top Forums Programming popen hangs program during cmd execution Post 302389076 by jim mcnamara on Friday 22nd of January 2010 01:40:54 PM
Old 01-22-2010
You are getting error output from ping - change the command
Code:
ping -c 3 www.primus.ca 2>&1 
# or if you don't want errors
ping -c 3 www.primus.ca > /dev/null

When you have a subprocess running it generates a system signal (which is being trapped by popen and reported). The signal is SIGTTOU. You cannot use popen without trapping stderr output or blocking signals.
 

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explain_popen_or_die(3) 				     Library Functions Manual					   explain_popen_or_die(3)

NAME
explain_popen_or_die - process I/O and report errors SYNOPSIS
#include <libexplain/popen.h> FILE *explain_popen_or_die(const char *command, const char *flags); DESCRIPTION
The explain_popen_or_die function is used to call the popen(3) system call. On failure an explanation will be printed to stderr, obtained from explain_popen(3), and then the process terminates by calling exit(EXIT_FAILURE). This function is intended to be used in a fashion similar to the following example: FILE *fp = explain_popen_or_die(command, flags); command The command, exactly as to be passed to the popen(3) system call. flags The flags, exactly as to be passed to the popen(3) system call. Returns: This function only returns on success, see popen(3) for more information. On failure, prints an explanation and exits. SEE ALSO
popen(3) process I/O explain_popen(3) explain popen(3) errors exit(2) terminate the calling process COPYRIGHT
libexplain version 0.52 Copyright (C) 2009 Peter Miller explain_popen_or_die(3)
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