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5.9 strfry

The function below addresses the perennial programming quandary: “How do I take good data in string form and painlessly turn it into garbage?” This is actually a fairly simple task for C programmers who do not use the GNU C Library string functions, but for programs based on the GNU C Library, the strfry function is the preferred method for destroying string data.

The prototype for this function is in string.h.

— Function: char * strfry (char *string)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

strfry creates a pseudorandom anagram of a string, replacing the input with the anagram in place. For each position in the string, strfry swaps it with a position in the string selected at random (from a uniform distribution). The two positions may be the same.

The return value of strfry is always string.

Portability Note: This function is unique to the GNU C Library.