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strncat(3)
NAME
  strncat, strncmp, strncpy - Perform operations on string

SYNOPSIS
  #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 );

LIBRARY
  Standard C Library (libc)

STANDARDS
  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.

PARAMETERS
  s1  Points to a location containing the first string or array.

  s2  Points to a location containing the second array.

  n   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.

DESCRIPTION
  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.

RETURN VALUES
  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).

SEE ALSO
  Functions: string(3), strcasecmp(3), strcat(3), strcmp(3), strcoll(3),
  strcpy(3), wcscoll(3), wcsncat(3), wcsncmp(3), wcsncpy(3)

  Standards: standards(5)

Index for Section 3

Alphabetical listing for S

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