BusyBox Bug and Patch Tracking
BusyBox
Main | My View | View Issues | Change Log | Docs
  

Viewing Issue Simple Details [ Jump to Notes ] [ View Advanced ] [ Issue History ] [ Print ]
ID Category Severity Reproducibility Date Submitted Last Update
0000133 [uClibc] Math Library minor always 03-06-05 10:19 12-08-05 12:36
Reporter jamie View Status public  
Assigned To uClibc
Priority normal Resolution fixed  
Status closed   Product Version 0.9.27
Summary 0000133: lrint, lrintf et al. math functions defined in headers but not in .so (breaks Xine)
Description #define _GNU_SOURCE
#include <math.h>
int main ()
{
  return lrintf (0.0);
}

This program fails to compile, citing a link time error, "undefined reference to `lrintf'".

However, there is no compile time warning, because the function is declared, it just isn't implemented in libm.so or libm.a.

The function _is_ implemented in <bits/mathinline.h>, however.

If __USE_EXTERN_INLINES is added to the compiler flags, then this program compiles and runs fine.

This omission breaks "Xine" (the audio/video player), where one of the codecs uses the lrintf() function. There are no compiler warnings because the function is declared, and in fact it builds fine because it's building a shared library; the problem is detected only at run time when the shared library cannot be loaded.

Glibc, from which the header files are derived, does have a definition of this function and its relatives in libm.so and libm.a. (Glibc 2.3.4 or thereabouts).
Additional Information
Attached Files

- Relationships

- Notes
(0000073)
jbrandmeyer
03-09-05 09:23

 sinf and cosf suffer the same problem. GCC bug# 20353 is somewhat related to this problem.
 
(0000078)
jamie
03-09-05 10:15

 The GCC bug is a bit different because GCC calls sinf and cosf even when the source program doesn't mention them, as an "optimisation".

But yes, they are related.

A quick hack for uclibc (not a perfect solution, but functional) for both these bugs would be:

float lrintf (float x) { return (float) lrint ((double) x); }
float sinf (float x) { return (float) sin ((double) x); }

Although in the case of functions like lrintf(), it's probably better to enable the inlined implementations when optimising.
 
(0000079)
jbrandmeyer
03-09-05 16:08

 lrintf remains outstanding, since lrint() is not defined, but it appears that sinf and cosf have been added by Mr. Anderson (using the technique you describe) a couple of days ago.
 
(0000080)
jamie
03-09-05 17:59

 There is an implementation of lrint() (and other functions) available in <bits/mathinline.h>, which can be used in a slightly dirty way to make the library implementations:

#include <math.h>
#define __NTH(f) __ # f
#include <bits/mathinline.h>

long int lrintf (float x) { __lrintf (x); }
long int lrint (double x) { __lrint (x); }
long int lrintl (long double x) { __lrintl (x); }

(Not tested).
You get the idea. No need to write actual math functions.

-- Jamie
 
(0000084)
psm
03-12-05 12:37

 see bug 0000144 for full math support
 
(0000753)
vapier
12-08-05 12:36

 latest svn has more math funcs
 

- Issue History
Date Modified Username Field Change
03-06-05 10:19 jamie New Issue
03-09-05 09:23 jbrandmeyer Note Added: 0000073
03-09-05 09:24 jbrandmeyer Issue Monitored: jbrandmeyer
03-09-05 10:15 jamie Note Added: 0000078
03-09-05 16:08 jbrandmeyer Note Added: 0000079
03-09-05 17:59 jamie Note Added: 0000080
03-12-05 12:37 psm Note Added: 0000084
03-16-05 11:52 andersen Assigned To mjn3 => uClibc
12-08-05 12:36 vapier Note Added: 0000753
12-08-05 12:36 vapier Status assigned => closed
12-08-05 12:36 vapier Resolution open => fixed

Copyright © 2000 - 2006 Mantis Group
Powered by Mantis Bugtracker