Index for Section 9r

Alphabetical listing for F

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ffs(9r)
NAME
  ffs - General: Finds the first set bit in a mask

SYNOPSIS
  int ffs(
	  long mask );

ARGUMENTS
  mask
      Specifies a bit mask with 0 (zero) or more bits set.

DESCRIPTION
  The ffs routine returns the bit position of the first bit you set in the
  mask argument.  The scan proceeds from the least significant bit to the
  most significant bit of the mask.

NOTES
  The ffs routine duplicates the behavior of the ffs instruction on the
  DIGITAL VAX series or computers.  It is not present in architectures that
  implement its function in hardware or through compiler inline substitution.

  The ffs routine is useful for translating bits in a bit mask into bit
  positions. For example, the signal handling code uses it to analyze the
  signal mask.

RETURN VALUES
  Upon successful completion, ffs returns the bit position of the first bit
  set in the mask. If no bits were set in the mask, ffs returns the value 0
  (zero).

Index for Section 9r

Alphabetical listing for F

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