How does calloc work in C code?

[samtronxindia]

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Code C - [expand]
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struct bpred_t *            /* branch predictory instance */
bpred_create(enum bpred_class class,    /* type of predictor to create */
         unsigned int bimod_size,   /* bimod table size */
         unsigned int l1size,   /* 2lev l1 table size */
         unsigned int l2size,   /* 2lev l2 table size */
         unsigned int meta_size,    /* meta table size */
         unsigned int shift_width,  /* history register width */
         unsigned int xor,      /* history xor address flag */
         unsigned int btb_sets, /* number of sets in BTB */ 
         unsigned int btb_assoc,    /* BTB associativity */
         unsigned int retstack_size) /* num entries in ret-addr stack */
{
  struct bpred_t *pred;
 
  if (!(pred = calloc(1, sizeof(struct bpred_t))))
    fatal("out of virtual memory");

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I want to know what the last part of the code i.e: If statement does..

 

[psurya1994]

Re: A C Code to Decipher

It just displays a error if you fall out of memory.

 

[samtronxindia]

Re: A C Code to Decipher

No thats ok but the reason why I posted it is , how is it doing that. For example can you explain me word by word that if statement please ...

 

[psurya1994]

Re: A C Code to Decipher

No thats ok but the reason why I posted it is , how is it doing that. For example can you explain me word by word that if statement please ...

In the statement: if (!(pred = calloc(1, sizeof(struct bpred_t))))
calloc:
You can see how calloc works here: https://www.cplusplus.com/reference/clibrary/cstdlib/calloc/
bpred_t:
ftp://ftp.mcs.anl.gov/pub/alice/10x10/sst-2.1/doc/html/structbpred__t.html

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