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strcpy(3) | Library Functions Manual | strcpy(3) |
NAME¶
stpcpy, strcpy, strcat - copy or catenate a string
LIBRARY¶
Standard C library (libc, -lc)
SYNOPSIS¶
#include <string.h>
char *stpcpy(char *restrict dst, const char *restrict src); char *strcpy(char *restrict dst, const char *restrict src); char *strcat(char *restrict dst, const char *restrict src);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
stpcpy():
Since glibc 2.10:
_POSIX_C_SOURCE >= 200809L
Before glibc 2.10:
_GNU_SOURCE
DESCRIPTION¶
- stpcpy()
- strcpy()
- These functions copy the string pointed to by src, into a string at the buffer pointed to by dst. The programmer is responsible for allocating a destination buffer large enough, that is, strlen(src) + 1. For the difference between the two functions, see RETURN VALUE.
- strcat()
- This function catenates the string pointed to by src, after the string pointed to by dst (overwriting its terminating null byte). The programmer is responsible for allocating a destination buffer large enough, that is, strlen(dst) + strlen(src) + 1.
An implementation of these functions might be:
char * stpcpy(char *restrict dst, const char *restrict src) {
char *p;
p = mempcpy(dst, src, strlen(src));
*p = '\0';
return p; } char * strcpy(char *restrict dst, const char *restrict src) {
stpcpy(dst, src);
return dst; } char * strcat(char *restrict dst, const char *restrict src) {
stpcpy(dst + strlen(dst), src);
return dst; }
RETURN VALUE¶
ATTRIBUTES¶
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
stpcpy (), strcpy (), strcat () | Thread safety | MT-Safe |
STANDARDS¶
STANDARDS¶
CAVEATS¶
The strings src and dst may not overlap.
If the destination buffer is not large enough, the behavior is undefined. See _FORTIFY_SOURCE in feature_test_macros(7).
strcat() can be very inefficient. Read about Shlemiel the painter.
EXAMPLES¶
#include <err.h> #include <stdio.h> #include <stdlib.h> #include <string.h> int main(void) {
char *p;
char *buf1;
char *buf2;
size_t len, maxsize;
maxsize = strlen("Hello ") + strlen("world") + strlen("!") + 1;
buf1 = malloc(sizeof(*buf1) * maxsize);
if (buf1 == NULL)
err(EXIT_FAILURE, "malloc()");
buf2 = malloc(sizeof(*buf2) * maxsize);
if (buf2 == NULL)
err(EXIT_FAILURE, "malloc()");
p = buf1;
p = stpcpy(p, "Hello ");
p = stpcpy(p, "world");
p = stpcpy(p, "!");
len = p - buf1;
printf("[len = %zu]: ", len);
puts(buf1); // "Hello world!"
free(buf1);
strcpy(buf2, "Hello ");
strcat(buf2, "world");
strcat(buf2, "!");
len = strlen(buf2);
printf("[len = %zu]: ", len);
puts(buf2); // "Hello world!"
free(buf2);
exit(EXIT_SUCCESS); }
SEE ALSO¶
2024-05-02 | Linux man-pages 6.8 |