Turning on modules in clang fails to build a simple project that imports CGBase.h and float.h

Originator:matt
Number:rdar://16221981 Date Originated:04/03/2014
Status:Open Resolved:No
Product:Developer Tools Product Version:Version 5.0.2 (5A3005)
Classification:Serious Bug Reproducible:Always
 
Summary:
If you import CGBase.h and float.h and use DBL_EPSILON, DBL_MIN, DBL_MAX or FLT_EPSILON, then you get compiler errors on the first build. Subsequent builds complete successfully.

The errors you receive are like this:
FloatHeaderBug.m:7:7: Use of undeclared identifier 'DBL_EPSILON'
FloatHeaderBug.m:8:7: Use of undeclared identifier 'DBL_MIN'
FloatHeaderBug.m:9:7: Use of undeclared identifier 'DBL_MAX'
FloatHeaderBug.m:10:7: Use of undeclared identifier 'FLT_EPSILON'

Steps to Reproduce:
1. Open sample project.
2. Build for iOS simulator 4-inch retina iPhone.
3. Notice errors.
4. Build.
5. Notice success.
6. Delete all derived data and modules cache (very important to delete the modules cache as well).
7. Goto step 2.

Expected Results:
The project builds first time.

Actual Results:
The project fails to build first time, but another build and it works.

Version:
Version 5.0.2 (5A3005)

Notes:


Configuration:


Attachments:
'FloatHeaderBug.zip' was successfully uploaded.

[Sample project here: https://github.com/mattjgalloway/CocoaBugs/tree/master/FloatHeaderBug]

Comments

I should add that if you turn off module support in the compiler, then this project builds successfully.

By matt at March 4, 2014, 3:37 p.m. (reply...)

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