strncat, strncmp, strncpy - Perform operations on string
#include <string.h>
char *strncat(
char *s1,
const char *s2,
size_t n ); int strncmp(
const char *s1,
const char *s2,
size_t n ); char *strncpy(
char *s1,
const char *s2,
size_t n );
Standard C Library (libc)
Interfaces documented on this reference page conform to
industry standards as follows:
strncat(), strncmp(), strncpy(): XSH4.2
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Points to a location containing the first string or array.
Points to a location containing the second array. Specifies
the number of bytes. In strncat(), n specifies the
maximum number of bytes to append; in strncmp(), n specifies
the maximum number of bytes to compare; and in
strncpy(), n specifies the number of bytes to copy.
The strncat() function appends no more than n bytes from
the array pointed to by the s2 parameter to the end of the
array pointed to by the s1 parameter. The initial byte of
the array pointed to by s2 overwrites the null byte at the
end of a string pointed to by s1. It then appends a null
byte to the result, and returns s1. When operating on
overlapping objects, the behavior of this function is
unreliable.
The strncmp() function compares the string or array
pointed to by the s1 parameter to the array pointed to by
the s2 parameter. The sign of a nonzero value returned by
strcmp() is determined by the sign of the difference
between the values of the first pair of bytes (both interpreted
as unsigned char) that differ in the two compared
objects. The strncmp() functions compares bytes until it
has compared n bytes or until it reaches a terminating
null byte.
The strncmp() function compares objects based on the
machine collating order. It does not use the locale-dependent
sorting order. Use the strcoll() or wcscoll() functions
for locale-dependent sorting.
The strncpy() function copies no more than n bytes from
the array pointed to by the s2 parameter to the array
pointed to by the s1 parameter. Bytes following a null
byte are not copied. When operating on overlapping locations,
the behavior of this function is unreliable. When
the location pointed to by the s2 parameter is an array
that is shorter than n bytes, null bytes are appended to
the s1 value until n bytes in all are written.
Upon successful completion, the strncat() and strncpy()
functions return a pointer to the resulting string or
array. [Tru64 UNIX] Otherwise, these functions return a
null pointer.
Upon successful completion, the strncmp() function returns
an integer whose value is greater than, equal to, or less
than 0 (zero), according to whether the value of the s1
object is greater than, equal to, or less than the value
of the s2 object. [Tru64 UNIX] When a successful comparison
cannot be made, strncmp() returns a value of 0 (zero).
Functions: string(3), strcasecmp(3), strcat(3), strcmp(3),
strcoll(3), strcpy(3), wcscoll(3), wcsncat(3), wcsncmp(3),
wcsncpy(3)
Standards: standards(5)
strncat(3)
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