Crate pkgconf 

Build helper utilities for parsing pkg-config output with proper --whole-archive support.

Problem

The standard pkg-config crate does not preserve the ordering of -Wl,--whole-archive and -l flags, which breaks linking for libraries that use constructor functions (like DPDK’s RTE_INIT macros). Additionally, it doesn’t properly distinguish between static and dynamic libraries based on file availability.

Solution

This crate parses pkg-config output directly and:

• Tracks --whole-archive regions from the pkg-config output
• Auto-detects static library availability by checking if lib<name>.a exists
• Excludes system directories (default: /usr) so system libs link dynamically
• Emits correct cargo link directives with proper modifiers (static:, +whole-archive, -bundle)

How Static Detection Works

For each -l<name> flag, the parser checks if lib<name>.a exists in any of the -L directories. If the .a file exists and is not under a system root directory, the library is linked statically. Otherwise, it’s linked dynamically (letting the system linker find the .so).

This mirrors the logic from the pkg-config crate’s is_static_available() function.

Link Kinds

Libraries are emitted with one of three link kinds:

Condition	Link Kind	Cargo Directive
No .a found (or in system dir)	Default	rustc-link-lib=name
.a exists, outside whole-archive region	Static	rustc-link-lib=static:-bundle=name
.a exists, inside whole-archive region	WholeArchive	rustc-link-lib=static:+whole-archive,-bundle=name

Example

use pkgconf::PkgConfigParser;

// Basic usage with default settings
let parser = PkgConfigParser::new();

parser.probe_and_emit(
    ["openssl", "libfoo"],
    None,
).expect("pkg-config failed");

Customization

use pkgconf::PkgConfigParser;

let parser = PkgConfigParser::new()
    // Add additional system roots (libs here link dynamically)
    .system_roots(["/usr", "/usr/local"])
    // Disable -bundle modifier (for non -sys crates)
    .no_bundle(false);

Structs

PkgConfigParser

Parser for pkg-config output that properly handles --whole-archive regions and auto-detects static library availability.

Enums

LinkKind

Represents how a library should be linked.

LinkerFlag

A parsed linker flag from pkg-config output.