golang/go

cmd/cgo: inject preamble before other include directives

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#35,315 opened on Nov 2, 2019

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FeatureRequestNeedsInvestigationcompiler/runtimehelp wanted

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Description

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

Yes

What did you see?

The cgo generated file _cgo_export.c includes stdlib.h before anything else (see here). It precludes the possibility to use some "include first" headers without errors or warnings, such as Python.

From the Python docs:

Since Python may define some pre-processor definitions which affect the standard headers on some systems, you must include Python.h before any standard headers are included.

Cgo should allow to inject a C preamble before any other include directive.

Contributor guide

Research direction
Review the cgo export code generation in out.go (around line 811) and modify the output order to write the user's preamble before the stdlib.h include.
Tech stack
go
Domain
backendbuild system
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GitGo
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35