enc2xs

enc2xs [options] [encoding-names...]

-o file
    Specifies the output C file name where the generated source code will be written.

-p prefix
    Sets a prefix for generated C symbols to avoid name clashes in the compiled module.

-C
    A convenience option that generates both the XS (eXtension Subsystem) and PM (Perl Module) files directly, facilitating module creation.

-Q
    Quiet mode; suppresses most informational messages during execution.

-v
    Verbose mode; displays more detailed information and progress messages.

-H
    Displays a brief help message explaining command usage and options, then exits.

-V
    Displays the version information of enc2xs and exits.

-A alias_file
    Specifies an additional alias file to include for encoding name lookups.

-M module_name
    Specifies the Perl module name for which the code is being generated (e.g., Encode::MyEncoding).

-g
    Generates a gperf lookup table for the encoding names, which can improve lookup performance.

-D
    Do not embed the encoding table data directly into the C code; instead, reference it externally.

-f
    Force overwrite of existing output files without prompting for confirmation.

-m name
    Generates code for a specific mapping table by its internal name.

-S dir
    Specifies the directory containing the encoding data source files.

-U
    Preserves the original table layout in the generated C code, rather than optimizing it for size or speed.

-X
    Generates only the XS (eXtension Subsystem) code, without the full C implementation.

enc2xs is a utility included with Perl's core Encode module. Its primary function is to convert character encoding mapping tables (often found in *.pl or *.dat files within the Encode distribution) into optimized C source code. This C code, once compiled into a shared library, can be dynamically loaded by Perl to provide highly efficient character encoding and decoding operations.

It is particularly useful for module developers who need to create custom Encode modules or for optimizing the performance of existing ones by compiling their character mapping data into native C code rather than relying on Perl-level data structures, which can be slower. It plays a crucial role in Perl's internationalization and localization capabilities, enabling fast and robust handling of various character sets.

enc2xs is primarily a development tool for Perl module authors and is not intended for general user-level character encoding conversion.

Its output is C source code, which requires a C compiler and the Perl development headers to be compiled into a loadable module. Directly interacting with enc2xs is typically only necessary when creating or customizing Encode modules, or when troubleshooting Encode performance issues.

enc2xs is a key component for optimizing the performance of Perl's Encode module. By converting encoding maps into compiled C code, it drastically reduces the overhead associated with character conversions, making it suitable for high-volume or performance-critical applications.

It is an essential tool for developers creating custom Encode modules, allowing them to integrate new or proprietary character encodings efficiently into the Perl ecosystem.

Unlike iconv, which is a standalone utility for character set conversion, enc2xs is a development tool that generates C source code for use within Perl's Encode module, primarily for internal optimization and extension, rather than direct user-facing conversion.

The enc2xs utility emerged as part of Perl's ongoing efforts to enhance its internationalization (i18n) and localization (L10n) capabilities, specifically with the development and maturation of the Encode module in Perl 5. It was introduced to provide a robust and performant mechanism for handling a wide array of character encodings by leveraging compiled C code for encoding/decoding tables, which significantly outperforms purely Perl-based implementations. Its development closely parallels the evolution of the Encode module itself, aiming to make Perl a first-class language for multi-byte character string processing.

perl(1), Encode(3pm), xsubpp(1), make(1)