The XGC Libraries: C/C++ Libraries for Real-Time Applications
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The srand function

Name

srand -- 

Synopsis 

#include <stdlib.h>

void srand (unsigned int seed);

Description

The srand function uses the argument as a seed for a new sequence of pseudo-random numbers to be returned by subsequent calls to rand. If srand is then called with the same seed value, the sequence of pseudo random numbers shall be repeated. If rand is called before any calls to srand have been made, the same sequence shall be generated as when srand is first called with a seed value of 1.

The implementation shall behave as if no library function calls the srand function.

Returns

The srand function returns no value.

Example

The following functions define a portable implementation of rand and srand. 

unsigned long next = 1;
int rand (void)
{
  next = next * 1103515245L + 12345L;
  return (unsigned int)((next > 16) & 0x7fff; 
}

void 
srand (unsigned int seed)
{
 next = seed;
}

See Also

The rand function

Implementation Notes

16-bit targets use the algorithm in the example above, and the value of RAND_MAX is 32767.
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