NAME

fcntl - file control system all

SYNOPSIS

fcntl FILEHANDLE,FUNCTION,SCALAR

DESCRIPTION

Implements the fcntl(2) function. You'll probably have to say

    use Fcntl;

first to get the correct constant definitions. Argument processing and value return works just like ioctl() below. For example:

    use Fcntl;
    fcntl($filehandle, F_GETFL, $packed_return_buffer)
        or die "can't fcntl F_GETFL: $!";

You don't have to check for defined() on the return from fnctl(). Like ioctl(), it maps a 0 return from the system call into ``0 but true'' in Perl. This string is true in boolean context and 0 in numeric context. It is also exempt from the normal -w warnings on improper numeric conversions.

Note that fcntl() will produce a fatal error if used on a machine that doesn't implement fcntl(2).

DISCLAIMER

We are painfully aware that these documents may contain incorrect links and misformatted HTML. Such bugs lie in the automatic translation process that automatically created the hundreds and hundreds of separate documents that you find here. Please do not report link or formatting bugs, because we cannot fix per-document problems. The only bug reports that will help us are those that supply working patches to the installhtml or pod2html programs, or to the Pod::HTML module itself, for which I and the entire Perl community will shower you with thanks and praises.

If rather than formatting bugs, you encounter substantive content errors in these documents, such as mistakes in the explanations or code, please use the perlbug utility included with the Perl distribution.

--Tom Christiansen, Perl Documentation Compiler and Editor

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