strcspn

SYNOPSIS
       #include 

       size_t strspn(const char *s, const char *accept);

       size_t strcspn(const char *s, const char *reject);

DESCRIPTION

strspn and strcspn calculate the initial length of a segment of s. strspn calculates the length of the segment which contains only characters in accept, while strcspn calculates the length of the segment which contains only characters not in reject.

NOTES

This is an input validation function made in heaven. Want to see if a string contains bad characters? Use this!

Say you write a CGI in C (a rare event these days, but bear with me), and you want to prevent people from putting in ../'s and the like. Just put a / in the reject parameter, and maybe a ., and call strcspn on the input!

The possibilities are endless, and if the length of reject or accept parameters gets really long (>128 bytes), then just switch functions...(assuming ASCII characters)

Part of the str functions list.