ITEM: AM4026L

xlc: What do the -H512 and -T512 options do?

Question:

what does -H do?   -T do?

Response:

ENV
BOS 3.2.5
xlc 1.3.0.0

DESC
Greg was looking through the /etc/xlc.cfg file and noticed that the
each of the compiler stanzas have lines that say "options = -H512,
-T512". Searching through the documentation (xlc User's and Ref 
Guides, InfoExplorer, etc.) he can't find a description of what these
options do.

ACTION
I too looked in all the normal 'xlc' documentation spaces, and can't
find any referenced to these options. However, if you look in the
man page dealing with ld, you find the text:
  -HNumber      Makes the value of the Number variable the boundary to
  which the .text, .data, and .loader sections are aligned within
  the  output object file.  To perform the specified file  boundary
  alignment, the binder inserts a pad section of an appropriate
  size prior to the .text, .data, and .loader sections of the out-
  put object file. If the value of the Number variable is 0, no
  padding is inserted.
  
  To ensure that the system loader can load a program, the .text
  section must  be aligned at least as strictly as is required by a
  .text CSECT.  For example, the  XL C Compiler generates code
  CSECTs with double-word alignment.  Thus, -H8, which specifies
  that the sections be aligned on a double-word boundary,  is ordi-
  narily the minimum value of the Number variable.  The xlc.cfg
  file causes the cc command to use the -H512 option when calling
  the ld command.
  
  The default is not to align the .text, .data, and .loader sec-
  tions of the output object file.

  -TNumber      Makes the value of the Number variable the starting ad-
  dress for the text segment of the output file.  The default value
  is 0.
  
  Note: The system loader relocates the .text section at run time,
  so the specified number affects only addresses listed  in address
  maps or printed by utilities such as the dump or nm command.

NEXT
cc



Support Line: xlc: What do the -H512 and -T512 options do? ITEM: AM4026L

Dated: July 1995 Category: N/A

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