AMX Mod X Documentation

AMX Mod X is a Metamod plugin for Half-Life 1. It provides a comprehensive scripting environment for the game engine and its mods.

Key capabilities include:

• Intercepting network messages.
• Logging events and commands.
• Intercepting client commands.
• Setting CVars (Console Variables).
• Modifying entities.
• Extending native scripting via modules (e.g., MySQL, Sockets).

If you use the PCRE POSIX interface (pcreposix.h) on a system that already has a POSIX regex library installed, you may encounter name clashes with functions like regcomp.

To avoid this, you can compile PCRE with a flag to rename these functions. For example, using -Dregcomp=PCREregcomp will rename the function to PCREregcomp. You must then use these new names in your application code.

CFLAGS='-Dregcomp=PCREregcomp -Dregexec=PCREregexec' ./configure

PCRE provides several API sets depending on your language and the data type you are processing:

• C APIs: Three distinct sets of functions for different character widths:
  • 8-bit library: Processes strings of bytes.
  • 16-bit library: Processes strings of 16-bit values.
  • 32-bit library: Processes strings of 32-bit values.
• C++ Wrapper: A set of C++ wrapper functions (provided by Google Inc.) used to call the 8-bit PCRE library from C++.
• POSIX-style C Wrapper: A set of C wrapper functions for the 8-bit library based on the POSIX regular expression API (found in libpcreposix). Note that while the interface is POSIX, the regex syntax and semantics remain Perl-compatible.

PCRE uses character tables for various functions. By default, pcre_chartables.c is a copy of pcre_chartables.c.dist which assumes ASCII coding.

To use a different set of tables based on your system's C locale, use the --enable-rebuild-chartables flag during the ./configure step. This invokes the dftables program, which uses ANSI C functions (like isalnum(), isalpha(), etc.) to build the tables.

Manual Customization: If you need to provide your own custom tables, edit pcre_chartables.c and rebuild PCRE. To prevent the build system from overwriting your changes, move pcre_chartables.c.dist out of the directory and replace it with your customized version.

./configure --enable-rebuild-chartables

When viewing long lists of commands via the help system, you can navigate through the entries using the following patterns:

• To see more entries: Use the command followed by the next page number: amx_help <command> <page_number>.
• To return to the beginning: Use the command followed by 1: amx_help <command> 1.

To see a list of available commands in the AMX Mod X console, use the help command pattern:

amx_help <command_name> <argument>

Note: The specific command prefix (e.g., amx_help) may vary depending on your configuration, but the pattern involves typing the help command followed by the command name in the console.

To generate the 8-digit hex CRC required for gamedata CRC sections, use the standalone tools/crc32 helper.

1. Build the tool using the provided build script.
2. Run the binary against your target file to get the CRC value.

# Build the tool
./tools/crc32/build.sh

# Generate the 8-digit hex CRC
./tools/crc32/crc32 <path-to-binary>

The pcreposix library provides a POSIX-style wrapper around the native PCRE (Perl-Compatible Regular Expressions) 8-bit library. While the API follows POSIX conventions, the underlying syntax and semantics remain Perl-based.

To use this API, include <pcreposix.h> and link against both -lpcreposix and -lpcre on Unix systems.

#include <pcreposix.h>

// Example usage pattern:
regex_t preg;
regcomp(&preg, "pattern", 0);
// ... use regexec ...
regfree(&preg);

PCRE quantifiers determine how many times a pattern element matches. By default, they are "greedy" (matching as much as possible). You can make them "ungreedy" (lazy) by appending a question mark ?.

Common Abbreviations

• * is equivalent to {0,}
• + is equivalent to {1,}
• ? is equivalent to {0,1}

Greediness Examples

• Greedy: /*.**/ applied to /* comment */ text /* comment */ will match the entire string from the first /* to the last */.
• Ungreedy: /*.*?*/ will match each comment individually.

PCRE_UNGREEDY Option

If the PCRE_UNGREEDY option is set, quantifiers are ungreedy by default, and you must append a ? to make them greedy.

# Greedy (matches as much as possible)
.* 

# Ungreedy/Lazy (matches as little as possible)
.*? 

# Doubled question mark (matches one digit by preference, but can match two if needed)
\d??