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srand(3c) [bsd man page]

RAND(3C)																  RAND(3C)

NAME
rand, srand - random number generator SYNOPSIS
srand(seed) int seed; rand() DESCRIPTION
The newer random(3) should be used in new applications; rand remains for compatibilty. Rand uses a multiplicative congruential random number generator with period 2**32 to return successive pseudo-random numbers in the range from 0 to (2**31)-1 on the VAX, and (2**15)-1 on the PDP-11. The generator is reinitialized by calling srand with 1 as argument. It can be set to a random starting point by calling srand with what- ever you like as argument. SEE ALSO
random(3) 7th Edition September 29, 1985 RAND(3C)

Check Out this Related Man Page

RAND(3) 						   BSD Library Functions Manual 						   RAND(3)

NAME
rand, rand_r, srand, sranddev -- bad random number generator LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <stdlib.h> int rand(void); int rand_r(unsigned *seed); void srand(unsigned seed); void sranddev(void); DESCRIPTION
These interfaces are obsoleted by arc4random(3). The rand() function computes a sequence of pseudo-random integers in the range of 0 to RAND_MAX (as defined by the header file <stdlib.h>). The srand() function sets its argument seed as the seed for a new sequence of pseudo-random numbers to be returned by rand(). These sequences are repeatable by calling srand() with the same seed value. If no seed value is provided, the functions are automatically seeded with a value of 1. The sranddev() function initializes a seed, using the random(4) random number device which returns good random numbers. However, the rand() function still remains unsuitable for cryptographic use. The rand_r() function provides the same functionality as rand(). A pointer to the context value seed must be supplied by the caller. SEE ALSO
arc4random(3), random(3), random(4) STANDARDS
The rand() and srand() functions conform to ISO/IEC 9899:1990 (``ISO C90''). The rand_r() function is as proposed in the POSIX.4a Draft #6 document. BSD
May 25, 1999 BSD

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