Hi Florian,

> * Lukasz Majewski:
> 
> > However, I've checked how it looks on the installed glibc:
> > root@y2038arm:/opt# nm /opt/lib/libc.so.6 | grep clock_gettime
> >
> > 000702bc t __GI___clock_gettime
> > 00070264 t __GI___clock_gettime64
> > 000702bc T __clock_gettime
> > 00070264 T __clock_gettime64
> > 000702bc t __clock_gettime_2
> > 000702bc T clock_gettime@@GLIBC_2.17
> > 000702bc T clock_gettime@GLIBC_2.4
> >
> > In the installed glibc the __clock_gettime64 is an external symbol.
> >  
> 
> All exported glibc symbols are versioned.  Chances are that nm does
> not look at the dynamic symbol table at all, so its output is
> misleading.  I usually use eu-readelf --symbols=.dynsym instead.

It seems like nm is correct here.

The output of installed libc.so:
root@y2038arm:/opt# readelf --symbols /opt/lib/libc.so.6 | grep clock_gettime
   846: 000702bd    64 FUNC    GLOBAL DEFAULT   12 __clock_gettime@@GLIBC_PRIVATE
  1515: 00070265    88 FUNC    GLOBAL DEFAULT   12 __clock_gettime64@@GLIBC_PRIVATE
  1751: 000702bd    64 FUNC    GLOBAL DEFAULT   12 clock_gettime@GLIBC_2.4
  1755: 000702bd    64 FUNC    GLOBAL DEFAULT   12 clock_gettime@@GLIBC_2.17
  3830: 00000000     0 FILE    LOCAL  DEFAULT  ABS clock_gettime.c
 10342: 000702bd    64 FUNC    LOCAL  DEFAULT   12 __clock_gettime_2
 10624: 00070265    88 FUNC    LOCAL  DEFAULT   12 __GI___clock_gettime64
 11251: 000702bd    64 FUNC    LOCAL  DEFAULT   12 __GI___clock_gettime
 11893: 000702bd    64 FUNC    GLOBAL DEFAULT   12 __clock_gettime
 11966: 000702bd    64 FUNC    GLOBAL DEFAULT   12 clock_gettime@GLIBC_2.4
 12166: 00070265    88 FUNC    GLOBAL DEFAULT   12 __clock_gettime64
 13749: 000702bd    64 FUNC    GLOBAL DEFAULT   12 clock_gettime@@GLIBC_2.17


The one when libmemusage.so is linked:

 readelf --symbols glibc/glibc-many-build/build/glibcs/arm-linux-gnueabi/glibc/libc.so | grep clock_gettime
   834: 0009a8e0   100 FUNC    GLOBAL DEFAULT   11 __clock_gettime@@GLIBC_PRIVATE
  1729: 0009a8e0   100 FUNC    GLOBAL DEFAULT   11 clock_gettime@GLIBC_2.4
  1733: 0009a8e0   100 FUNC    GLOBAL DEFAULT   11 clock_gettime@@GLIBC_2.17
  3658: 00000000     0 FILE    LOCAL  DEFAULT  ABS clock_gettime.c
  9435: 0009a774   364 FUNC    LOCAL  DEFAULT   11 __clock_gettime64
 10187: 0009a8e0   100 FUNC    LOCAL  DEFAULT   11 __clock_gettime_2
 10478: 0009a774   364 FUNC    LOCAL  DEFAULT   11 __GI___clock_gettime64
 11124: 0009a8e0   100 FUNC    LOCAL  DEFAULT   11 __GI___clock_gettime
 11729: 0009a8e0   100 FUNC    GLOBAL DEFAULT   11 __clock_gettime
 11802: 0009a8e0   100 FUNC    GLOBAL DEFAULT   11 clock_gettime@GLIBC_2.4
 13564: 0009a8e0   100 FUNC    GLOBAL DEFAULT   11 clock_gettime@@GLIBC_2.17


The results are the same -> __clock_gettime64 is GLOBAL on installed glibc
and LOCAL when linking libmemusage.so.


Best regards,

Lukasz Majewski

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