STRING(3) STRING(3) NAME strcat, strncat, strcmp, strncmp, strcpy, strncpy, strlen, strchr, strrchr, strpbrk, strspn, strcspn, strtok, index, rindex - string operations SYNOPSIS #include <string.h> char *s; char *strcat(s1, s2) char *strchr(s, c) char *s1, *s2; char *s; int c; char *strncat(s1, s2, n) char *s1, *s2; char *strrchr(s, c) int n; char *s; int c; int strcmp(s1, s2) char *s1, *s2; char *strpbrk(s1, s2) char *s1, *s2; int strncmp(s1, s2, n) char *s1, *s2; int strspn(s1, s2) int n; char *s1, *s2; char *strcpy(s1, s2) int strcspn(s1, s2) char *s1, *s2; char *s1, *s2; char *strncpy(s1, s2, n) char *strtok(s1, s2) char *s1, *s2; char *s1, *s2; int n; char *strdup(s) int strlen(s) char *s; DESCRIPTION The arguments s1, s2 and s point to null-terminated strings. The functions strcat, strncat, strcpy, and strncpy all alter s1. These functions do not check for overflow of the array pointed to by s1. Strcat appends a copy of string s2 to the end of string s1. Strncat appends at most n characters. Each returns a pointer to the null-terminated result. Strcmp compares its arguments and returns an integer less than, equal to, or greater than 0, according as s1 is lexi- cographically less than, equal to, or greater than s2. Strncmp makes the same comparison but looks at at most n characters. Strcpy copies string s2 to s1, stopping after the null char- acter has been copied. Strncpy copies exactly n characters, truncating s2 or adding null characters to s1 if necessary. STRING(3) STRING(3) The result will not be null-terminated if the length of s2 is n or more. Each function returns s1. Strlen returns the number of characters in s, not including the terminating null character. Strchr (strrchr) returns a pointer to the first (last) occurrence of character c in string s, or 0 if c does not occur in the string. The null character terminating a string is considered to be part of the string. Index and rindex are obsolete names for strchr and strrchr. Strpbrk returns a pointer to the first occurrence in string s1 of any character from string s2, 0 if no character from s2 exists in s1. Strspn (strcspn) returns the length of the initial segment of string s1 which consists entirely of characters from (not from) string s2. Strtok considers the string s1 to consist of a sequence of zero or more text tokens separated by spans of one or more characters from the separator string s2. The first call, with pointer s1 specified, returns a pointer to the first character of the first token, and will have written a null character into s1 immediately following the returned token. The function keeps track of its position in the string between separate calls; subsequent calls, signified by s1 being 0, will work through the string s1 immediately follow- ing that token. The separator string s2 may be different from call to call. When no token remains in s1, 0 is returned. Strdup returns a pointer to a distinct copy of the null- terminated string s in space obtained from malloc(3) or 0 if no space can be obtained. SEE ALSO memory(3) BUGS Strcmp and strncmp use native character comparison, which is signed on some machines, unsigned on others, but consistent on ASCII characters. The outcome of overlapping moves varies among implementa- tions.