$^F The maximum system file descriptor, ordinarily 2. System file descriptors are passed to exec()ed processes, while higher file descriptors are not. Also, during an open(), system file descriptors are preserved even if the open() fails (ordinary file descriptors are closed before the open() is attempted). The close-on-exec status of a file descriptor will be decided according to the value of $^F when the corresponding file, pipe, or socket was opened, not the time of the exec().

NAME DESCRIPTION VariablesDatatypes What is an "IV"? Working with SVs Offsets What's Really Stored in an SV? Working with AVs Working with HVs Hash API Extensions AVs, HVs and undefined values References Blessed References and Class Objects Creating New Variables Reference Counts and Mortality Stashes and Globs Double-Typed SVs Read-Only Values Copy on Write Magic Variables Assigning Magic Magic Virtual Tables Finding Magic Understanding the Magic of Tied Hashes and Arrays Localizing changes

sysopen FILEHANDLE,FILENAME,MODE sysopen FILEHANDLE,FILENAME,MODE,PERMS Opens the file whose filename is given by FILENAME, and associates it with FILEHANDLE. If FILEHANDLE is an expression, its value is used as the real filehandle wanted; an undefined scalar will be suitably autovivified. This function calls the underlying operating system's open(2) function with the parameters FILENAME, MODE, and PERMS. The possible values and flag bits of the MODE parameter are system-dependent; they are ava

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qx/STRING/ Generalized quotes. See Quote-Like Operators in perlop.

$! When referenced, $! retrieves the current value of the C errno integer variable. If $! is assigned a numerical value, that value is stored in errno . When referenced as a string, $! yields the system error string corresponding to errno . Many system or library calls set errno if they fail, to indicate the cause of failure. They usually do not set errno to zero if they succeed. This means errno , hence $! , is meaningful only immediately after a failure: if (open my $fh, "<", $filename)

NAME SYNOPSIS DESCRIPTIONHow to Export Selecting What to Export How to Import Advanced FeaturesSpecialised Import Lists Exporting Without Using Exporter's import Method Exporting Without Inheriting from Exporter Module Version Checking Managing Unknown Symbols Tag Handling Utility Functions Generating Combined Tags AUTOLOADed Constants Good PracticesDeclaring @EXPORT_OK and Friends Playing Safe What Not to Export SEE ALSO LICENSE NAME Exporter - Implements default import method for modu

die LIST die raises an exception. Inside an eval the error message is stuffed into $@ and the eval is terminated with the undefined value. If the exception is outside of all enclosing evals, then the uncaught exception prints LIST to STDERR and exits with a non-zero value. If you need to exit the process with a specific exit code, see exit. Equivalent examples: die "Can't cd to spool: $!\n" unless chdir '/usr/spool/news'; chdir '/usr/spool/news' or die "Can't cd to spool: $!\n" If the last ele