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Diffstat (limited to 'pod/modpods/Open2.pod')
-rw-r--r-- | pod/modpods/Open2.pod | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/pod/modpods/Open2.pod b/pod/modpods/Open2.pod new file mode 100644 index 0000000000..19f0369cfd --- /dev/null +++ b/pod/modpods/Open2.pod @@ -0,0 +1,33 @@ +=head1 NAME + +IPC::Open2, open2 - open a process for both reading and writing + +=head1 SYNOPSIS + + use IPC::Open2; + $pid = open2('rdr', 'wtr', 'some cmd and args'); + # or + $pid = open2('rdr', 'wtr', 'some', 'cmd', 'and', 'args'); + +=head1 DESCRIPTION + +The open2() function spawns the given $cmd and connects $rdr for +reading and $wtr for writing. It's what you think should work +when you try + + open(HANDLE, "|cmd args"); + +open2() returns the process ID of the child process. It doesn't return on +failure: it just raises an exception matching C</^open2:/>. + +=head1 WARNING + +It will not create these file handles for you. You have to do this yourself. +So don't pass it empty variables expecting them to get filled in for you. + +Additionally, this is very dangerous as you may block forever. +It assumes it's going to talk to something like B<bc>, both writing to +it and reading from it. This is presumably safe because you "know" +that commands like B<bc> will read a line at a time and output a line at +a time. Programs like B<sort> that read their entire input stream first, +however, are quite apt to cause deadlock. See L<open3> for an alternative. |