```{index} single: constant; POSIX function ``` ```{index} single: POSIX::constant; Perl function ``` # constant Look up a POSIX constant by name. ## Synopsis ```perl my $enoent = POSIX::constant("ENOENT"); ``` ## What you get back The integer or floating-point value of the named constant, or `undef` if the name is not known. ## Differences from upstream Fully compatible with upstream POSIX. Ordinary code should import the constant by name rather than going through this accessor — it exists mainly for tooling and introspection.