ref: c116550e6a41572796e4db65e4f6acbcb3d9d6f8
dir: /man/10/strcat/
.TH STRCAT 10.2 .SH NAME strcat, strcmp, strncmp, strcpy, strncpy, strlen, strchr, strrchr, strdup, strstr \- string operations .SH SYNOPSIS .ta \w'\fLchar* \fP'u .B char* strcat(char *s1, char *s2) .PP .B int strcmp(char *s1, char *s2) .PP .B int strncmp(char *s1, char *s2, long n) .PP .B char* strcpy(char *s1, char *s2) .PP .B char* strncpy(char *s1, char *s2, long n) .PP .B long strlen(char *s) .PP .B char* strchr(char *s, char c) .PP .B char* strrchr(char *s, char c) .PP .B char* strdup(char *s) .PP .B char* strstr(char *s1, char *s2) .SH DESCRIPTION The arguments .I s1, s2 and .I s point to null-terminated strings. The functions .IR strcat , .IR strcpy , and .I strncpy all alter .IR s1 . These functions do not check for overflow of the array pointed to by .IR s1 . .PP .I Strcat appends a copy of string .I s2 to the end of string .IR s1 , and returns a pointer to the null-terminated result. .PP .I Strcmp compares its arguments and returns an integer less than, equal to, or greater than 0, according as .I s1 is lexicographically less than, equal to, or greater than .IR s2 . .I Strncmp makes the same comparison but examines at most .I n bytes. The comparisons are made with unsigned bytes. .PP .I Strcpy copies string .I s2 to .IR s1 , stopping after the null byte has been copied. .I Strncpy copies exactly .I n bytes, truncating .I s2 or adding null bytes to .I s1 if necessary. The result will not be null-terminated if the length of .I s2 is .I n or more. Each function returns .IR s1 . .PP .I Strlen returns the number of bytes in .IR s , not including the terminating null byte. .PP .I Strchr .RI ( strrchr ) returns a pointer to the first (last) occurrence of byte .I c in string .IR s , or .L 0 if .I c does not occur in the string. The null byte terminating a string is considered to be part of the string. .PP .I Strdup returns a pointer to a distinct copy of the null-terminated string .I s in space obtained from .IR malloc (10.2) or .L 0 if no space can be obtained. .PP .I Strstr returns a pointer to the first occurrence of .I s2 as a substring of .IR s1 , or 0 if there is none. If .I s2 is the null string, .I strstr returns .IR s1 . .SH SOURCE .B /libkern/str*.c .br .B /libkern/str*-\fIobjtype\fP.c .br .B /lib9/strdup.c .SH SEE ALSO .IR memory (10.2), .IR rune (10.2) .SH BUGS These routines know nothing about .SM UTF. Use the routines in .IR rune (10.2) as appropriate. Note, however, that the definition of UTF guarantees that .I strcmp compares UTF strings correctly. .PP The outcome of overlapping moves varies among implementations. .PP Note the absence of ANSI C's .IR strncat , .IR strpbrk , .IR strspn , .IR strcspn and .IR strtok , but the presence of .IR strdup . ...strtod.c strtol.c strtoul.c strtoll.c