C code snippet dot operator syntax

Question

I encountered the following code snippet within a cstartup file for a cortex m0 micro - cstartup_M.c

#pragma location = ".intvec"
__root const intvec_elem __vector_table[] =
{
  { .__ptr = __sfe( "CSTACK" ) },
  __iar_program_start,

  NonMaskableInt_Handler,
  HardFault_Handler,

Could someone please explain the syntax within the line: { .__ptr = __sfe( "CSTACK" ) },

Specifically:

What is the purpose of the additional code block?
What is going on here: .__ptr?

Could it be a designated initializer syntax? – Sourav Ghosh Feb 17 '16 at 10:29 — Sourav Ghosh, Feb 17 '16 at 10:29

score 3 · Accepted Answer · answered Feb 17 '16 at 10:30

3

That's the new C99 initialization syntax. An initializer of the form

.field = value

initializes structure member field to value instead of initializing the next structure member in order.

answered Feb 17 '16 at 10:30

fuz

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well, that's embarrassing, I should have known that! An answer within 30 secs. Fair play! – Gregory Kuhn Feb 17 '16 at 10:32
@GregoryKuhn Happens to the best of us. Syntax is hard to search for. – fuz Feb 17 '16 at 10:33
"the new C99 initialization syntax" It's 17 years old... :) – Lundin Feb 17 '16 at 10:46
@Lundin Well, for Microsoft it's still new. – fuz Feb 17 '16 at 11:08

C code snippet dot operator syntax

1 Answers1